General Biology 1 Quarter 1 - Module 1: Cell Theory PDF

lOMoARcPSD|42657537 Cell theory M 1 Oral Communication (Davao City National High School) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Download...

lOMoARcPSD|42657537 Cell theory M 1 Oral Communication (Davao City National High School) Scan to open on Studocu Studocu is not sponsored or endorsed by any college or university Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 SENIOR HIGH SCHOOL General Biology 1 Quarter 3 – Module 1: Title: Cell Theory Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 General Biology 1 – Grade 12 Alternative Delivery Mode Quarter 1 – Module 1: Cell Theory First Edition, 2020 Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for exploitation of such work for profit. Such agency or office may, among other things, impose as a condition the payment of royalties. Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this module are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them. Published by the Department of Education Secretary: Leonor Magtolis Briones Undersecretary: Diosdado M. San Antonio Development Team of the Module Writers: Ma. Angelica D. Guban Editors: Evelyn D. Dulino, Ph.D. Reviewer: Ryan Cutamora Illustrator: Layout Artist: Management Team: Dr. Carlito D. Rocafort Dr. Job S. Zape Jr. Eugene Adrao Elaine Balaogan Elpidia B. Bergado Ed.D, CID Chief Noel S. Ortega, Division EPS-LRMS Dr. Josephine Monzaga Printed in the Philippines by ________________________ Department of Education – Schools Division Office of Cavite Office Address: Capitol Compound, Brgy. Luciano Trece Martires City, Cavite Telefax: (046) 419 139 / 419-0328 E-mail Address: [email protected] Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 12 General Biology 1 Quarter 1 – Module 1: Cell Theory Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 Introductory Message For the facilitator: Welcome to the General Biology 1-Grade 12 Alternative Delivery Mode (ADM) Module on Cell Theory! This module was collaboratively designed, developed and reviewed by educators both from public and private institutions to assist you, the teacher or facilitator in helping the learners meet the standards set by the K to 12 Curriculum while overcoming their personal, social, and economic constraints in schooling. This learning resource hopes to engage the learners into guided and independent learning activities at their own pace and time. Furthermore, this also aims to help learners acquire the needed 21st century skills while taking into consideration their needs and circumstances. In addition to the material in the main text, you will also see this box in the body of the module: Notes to the Teacher This contains helpful tips or strategies that will help you in guiding the learners. As a facilitator you are expected to orient the learners on how to use this module. You also need to keep track of the learners' progress while allowing them to manage their own learning. Furthermore, you are expected to encourage and assist the learners as they do the tasks included in the module. For the learner: Welcome to the General Biology 1 Alternative Delivery Mode (ADM) Module on Cell Theory! The hand is one of the most symbolized part of the human body. It is often used to depict skill, action and purpose. Through our hands we may learn, create and accomplish. Hence, the hand in this learning resource signifies that you as a learner is capable and empowered to successfully achieve the relevant competencies and skills at your own pace and time. Your academic success lies in your own hands! 2 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 This module was designed to provide you with fun and meaningful opportunities for guided and independent learning at your own pace and time. You will be enabled to process the contents of the learning resource while being an active learner. This module has the following parts and corresponding icons: What I Need to Know This will give you an idea of the skills or competencies you are expected to learn in the module. What I Know This part includes an activity that aims to check what you already know about the lesson to take. If you get all the answers correct (100%), you may decide to skip this module. What’s In This is a brief drill or review to help you link the current lesson with the previous one. What’s New In this portion, the new lesson will be introduced to you in various ways such as a story, a song, a poem, a problem opener, an activity or a situation. What is It This section provides a brief discussion of the lesson. This aims to help you discover and understand new concepts and skills. What’s More This comprises activities for independent practice to solidify your understanding and skills of the topic. You may check the answers to the exercises using the Answer Key at the end of the module. What I Have Learned This includes questions or blank sentence/paragraph to be filled in to process what you learned from the lesson. What I Can Do This section provides an activity which will help you transfer your new knowledge or skill into real life situations or concerns. Assessment This is a task which aims to evaluate your level of mastery in achieving the learning competency. Additional Activities In this portion, another activity will be given to you to enrich your knowledge or skill of the lesson learned. This also tends retention of learned concepts. Answer Key This contains answers to all activities in the module. At the end of this module you will also find: References This is a list of all sources used in developing this module. The following are some reminders in using this module: 3 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 1. Use the module with care. Do not put unnecessary mark/s on any part of the module. Use a separate sheet of paper in answering the exercises. 2. Don’t forget to answer What I Know before moving on to the other activities included in the module. 3. Read the instruction carefully before doing each task. 4. Observe honesty and integrity in doing the tasks and checking your answers. 5. Finish the task at hand before proceeding to the next. 6. Return this module to your teacher/facilitator once you are through with it. If you encounter any difficulty in answering the tasks in this module, do not hesitate to consult your teacher or facilitator. Always bear in mind that you are not alone. We hope that through this material, you will experience meaningful learning and gain deep understanding of the relevant competencies. You can do it! What I Need to Know This module was designed and written with you in mind. It is here to help you master the cell theory. The scope of this module permits it to be used in many different learning situations. The language used recognizes the diverse vocabulary level of students. The lessons are arranged to follow the standard sequence of the course. But the order in which you read them can be changed to correspond with the textbook you are now using. The module is divided into two lessons, namely: Lesson 1 – Going Back in Time: Spontaneous Generation Lesson 2 – Postulates of the cell theory After going through this module, you are expected to: 1. Describe the tenets of spontaneous generation 2. Explain the postulates of the cell theory 3. Name some scientist who worked for the formulation of the cell theory 4 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 What I Know Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper. 1. He discovered that all plants were made of cells, which contributed to the development of the cell theory: A. Anton van Leeuwenhoek B. Robert Hooke C. Theodor Schwann D. Matthias Schleiden 2. He advanced the cell theory with his conclusion that cells could only come from other cells: A. Anton van Leeuwenhoek B. Rudolph Virchow C. Theodor Schwann D. Robert Hooke 3. Which of the following is NOT one of the main components of the cell theory? A. cells must contain DNA B. all living things are made of cells C. cells can only come from other cells D. cells are the basic unit of life 4. Rudolph Virchow's observations helped to disprove was commonly held belief of the time? A. evolution B. the existence of molecules C. spontaneous generation D. atomic models 5. Which technology was essential for the development of the cell theory? A. Telescopes B. Antiseptics C. Microwaves D. Microscopes 6. Which of the following is a key difference between Needham's and Spallanzani's experiments testing the idea of spontaneous generation? A. Needham heated his broth while Spallanzani did not. B. Spallanzani heated his broth while Needham did not C. Needham sealed his flasks tightly while Spallanzani did not. D. Spallanzani sealed his flasks tightly while Needham did not. 7. Which scientist disproved spontaneous generation of large organisms by showing maggots came from flies not from rotting meat? A. Redi B. Needham C. Spallanzani 5 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 D. Pasteur 8. Who stated that cell comes from pre-existing cell? A. Matthias Schleiden B. Theodor Schwann C. Rudolf Virchow D. John Needham 9. Which scientist designed a special flask that allowed air in but kept microbes out and once and for all disproved spontaneous generation? A. Redi B. Needham C. Spallanzani D. Pasteur 10. This term means life comes from non-life A. Abiotic B. Biotic C. Abiogenesis D. Biogenesis 11. Which of the following statements is NOT part of the cell theory? A. Cells are the basic unit of structure and function in all living things. B. All cells are produced from other cells. C. Only animal cells are composed of cells. D. All living things are composed of cells 12. It is one way in which all living things on Earth are alike. A. All living things have hair B. All living things are made of cells and come from other cells C. The cells of all living things have chloroplast D. All living things can move 13. The first part of the cell theory states: “What happens in cell theory, stay in Cell Theory” A. True B. False C. Sometimes true D. Sometimes false 14. Why are microscopes important when studying most cells? A. Most cells are very large B. Most cells are very small C. Most cells move very quickly D. Most cells are dead 15. Which of the following scientists concluded that all ANIMALS are made up of cells? A. Rudolf Virchow B. Matthias Schleiden C. Robert Hooke D. Theodor Schwann 6 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 Lesson Cell Theory 1 GOING BACK IN TIME! Where does life come from? Religion, philosophy, and science have all wrestled with this question. One of the oldest explanations was the theory of spontaneous generation, which can be traced back to the ancient Greeks and was widely accepted through the middle Ages. Most biologists believe that life arose spontaneously from inanimate matter, but the details of how this could have happened remain unknown and the time scale was long. What is it really all about? What are the real tenets of the cell theory? That is what you are going to find out. What’s In Let’s see what you got, find the right match! Direction: Match the items on the left to the items on the right. Write the letter and word for each number. 1. Determined that all animals were made of cells a. Hooke 2. Looked at cork and called it “cells” b. Virchow 3. Determined that all cells come from pre-existing cells c. Schwann 4. Invented the first compound microscope d. Schleiden 5. Determined that all plants are made up of cell e. Leeuwenhoek Notes to the Teacher Have the students recall the parts and function of the microscope. Impress to the students that the invention of the microscope paved the way for the formulation of the cell theory. What’s New BIG QUESTIONS for your BIG MIND! A. In the past, what is the people’s understanding about cell? B. What was their perception about the origin of life? 7 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 C. How did they determine these perceptions? Find out the answers from the selection below: The Theory of Spontaneous Generation The Greek philosopher Aristotle (384–322 BC) was one of the earliest recorded scholars to articulate the theory of spontaneous generation, the notion that life can arise from nonliving matter. Aristotle proposed that life arose from nonliving material if the material contained pneuma (“vital heat”). As evidence, he noted several instances of the appearance of animals from environments previously devoid of such animals, such as the seemingly sudden appearance of fish in a new puddle of water. This theory persisted into the seventeenth century, when scientists undertook additional experimentation to support or disprove it. By this time, the proponents of the theory cited how frogs simply seem to appear along the muddy banks of the Nile River in Egypt during the annual flooding. Others observed that mice simply appeared among grain stored in barns with thatched roofs. When the roof leaked and the grain molded, mice appeared. Jan Baptista van Helmont, a seventeenth century Flemish scientist, proposed that mice could arise from rags and wheat kernels left in an open container for 3 weeks. In reality, such habitats provided ideal food sources and shelter for mouse populations to flourish. However, one of van Helmont’s contemporaries, Italian physician Francesco Redi (1626–1697), performed an experiment in 1668 that was one of the first to refute the idea that maggots (the larvae of flies) spontaneously generate on meat left out in the open air. He predicted that preventing flies from having direct contact with the meat would also prevent the appearance of maggots. Redi left meat in each of six containers (Figure 1). Two were open to the air, two were covered with gauze, and two were tightly sealed. His hypothesis was supported when maggots developed in the uncovered jars, but no maggots appeared in either the gauze-covered or the tightly sealed jars. He concluded that maggots could only form when flies were allowed to lay eggs in the meat, and that the maggots were the offspring of flies, not the product of spontaneous generation. Figure 1. Francesco Redi’s experimental setup consisted of an open container, a container sealed with a cork top, and a container covered in mesh that let in air but not flies. Maggots only appeared on the meat in the open container. However, maggots were also found on the gauze of the gauze-covered container. In 1745, John Needham (1713–1781) published a report of his own experiments, in which he briefly boiled broth infused with plant or animal matter, hoping to kill all preexisting microbes. He then sealed the flasks. After a few days, Needham observed that the broth had become cloudy and a single drop contained 8 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 numerous microscopic creatures. He argued that the new microbes must have arisen spontaneously. In reality, however, he likely did not boil the broth enough to kill all preexisting microbes. Lazzaro Spallanzani (1729–1799) did not agree with Needham’s conclusions, however, and performed hundreds of carefully executed experiments using heated broth. As in Needham’s experiment, broth in sealed jars and unsealed jars was infused with plant and animal matter. Spallanzani’s results contradicted the findings of Needham: Heated but sealed flasks remained clear, without any signs of spontaneous growth, unless the flasks were subsequently opened to the air. This suggested that microbes were introduced into these flasks from the air. In response to Spallanzani’s findings, Needham argued that life originates from a “life force” that was destroyed during Spallanzani’s extended boiling. Any subsequent sealing of the flasks then prevented new life force from entering and causing spontaneous generation (Figure 2). Figure 2. (a) Francesco Redi, who demonstrated that maggots were the offspring of flies, not products of spontaneous generation. (b) John Needham, who argued that microbes arose spontaneously in broth from a “life force.” (c) Lazzaro Spallanzani, whose experiments with broth aimed to disprove those of Needham. The debate over spontaneous generation continued well into the nineteenth century, with scientists serving as proponents of both sides. To settle the debate, the Paris Academy of Sciences offered a prize for resolution of the problem. Louis Pasteur, a prominent French chemist who had been studying microbial fermentation and the causes of wine spoilage, accepted the challenge. In 1858, Pasteur filtered air through a gun-cotton filter and, upon microscopic examination of the cotton, found it full of microorganisms, suggesting that the exposure of a broth to air was not introducing a “life force” to the broth but rather airborne microorganisms. Later, Pasteur made a series of flasks with long, twisted necks (“swan- neck” flasks), in which he boiled broth to sterilize it (Figure 3). His design allowed air inside the flasks to be exchanged with air from the outside, but prevented the introduction of any airborne microorganisms, which would get caught in the twists and bends of the flasks’ necks. If a life force besides the airborne microorganisms were responsible for microbial growth within the sterilized flasks, it would have access to the broth, whereas the microorganisms would not. He correctly predicted that sterilized broth in his swan-neck flasks would remain sterile as long as the swan necks remained intact. However, should the necks be 9 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 broken, microorganisms would be introduced, contaminating the flasks and allowing microbial growth within the broth. Pasteur’s set of experiments irrefutably disproved the theory of spontaneous generation and earned him the prestigious Alhumbert Prize from the Paris Academy of Sciences in 1862. In a subsequent lecture in 1864, Pasteur articulated “Omne vivum ex vivo” (“Life only comes from life”). In this lecture, Pasteur recounted his famous swan-neck flask experiment, stating that “life is a germ and a germ is life. Never will the doctrine of spontaneous generation recover from the mortal blow of this simple experiment. To Pasteur’s credit, it never has. See the details of his experiment below: Figure 3. (a) French scientist Louis Pasteur, who definitively refuted the long-disputed theory of spontaneous generation. (b) The unique swan-neck feature of the flasks used in Pasteur’s experiment allowed air to enter the flask but prevented the entry of bacterial and fungal spores. (c) Pasteur’s experiment consisted of two parts. In the first part, the broth in the flask was boiled to sterilize it. When this broth was cooled, it remained free of contamination. In the second part of the experiment, the flask was boiled and then the neck was broken off. The broth in this flask became contaminated. (Credit by: modification of work by “Wellcome Images”/Wikimedia Commons What is It 10 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 Little is much: Understanding the Cork The discovery of cells was made possible by the development of the microscope in the 17th century. In 1665, an English scientist, Robert Hooke, examined a thin slice of cork under the microscope. He observed that the piece of cork was composed of many tiny compartments which resembled little rooms with surrounding wall. Hooke named these compartments cells. The cells that Hooke observed were not living. He concentrated his study only on the structure, particularly on the cell wall, and did not pursue his investigation of the cell content. In 1674, the Dutch inventor Antoine Van Leuwenhoek observed red blood cells, sperms and a myriad of single- celled organisms in pond water. He discovered free cells and observed the nucleus within some red blood cells. Leuwenhoek was a contemporary of Robert Hooke. He had more success in living cells in action despite his smaller, simpler, handled microscopes. Over the next 200 years after Hooke, another scientist, a Scottish botanist named Robert Brown, made a general conclusion in 1831. He discovered the nucleus and theorized that this structure is a fundamental and a constant component of the cell. In 1835, a French biologist, Felix Dujardin found out that living cells contained an internal substance. Not knowing exactly what this substance was, Dujardin gave it the name sarcode. It was a Bohemian physiologist, Jan Evangelista Purkinje, who made a thorough investigation of this internal material. He gave it the name protoplasm, a term coined for the colloidal substance in the cell which is currently known as cytoplasm. In 1838, Matthias Schleiden, a German botanist, stated that all plants are composed of cells. After him, in 1839, Theodore Schwann, a German zoologist, concluded that all animals are composed of cells. Jointly, Schleiden and Schwann came out with the theory that all living things are composed of cells. Twenty years later, in 1858, a German biologist, Rudolph Virchow, theorized that all living cells come from pre-existing living cells. His conclusion arose from observing dividing cells while he was at work. These observations became the major components of the cell theory. The cell theory states that: 1. All living things are composed of one or more cells and cell products. 2. All living cells come from other living cells by the process of cell division. 3. Cells are the basic units of structure and function on organism What’s More SPONTANEOUS GENERATION SUMMARY TABLE 11 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 Scientists and date Experiment performed Main idea (Brief description) 1. 2. 3. 4. 5. CELL THEORY SUMMARY TABLE Direction: The table below indicates events that led to the cell theory. Complete the table by filling in the blank spaces. Date Scientist Discovery 1665 a. ___________________ Examine the thin slice of cork b. ______________ Anton Van c. ____________________ Leeuwenhoek 1838 Matthias Schleiden d. ___________________ e. _______________ f. ____________________ Stated that all animals are made up of cell 1858 g. ____________________ h. ____________________ 12 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 What I Have Learned 1. The theory of spontaneous generation states that life arose from nonliving matter. It was a long-held belief dating back to Aristotle and the ancient Greeks. 2. Experimentation by Francesco Redi in the seventeenth century presented the first significant evidence refuting spontaneous generation by showing that flies must have access to meat for maggots to develop on the meat. Prominent scientists designed experiments and argued both in support of (John Needham) and against (Lazzaro Spallanzani) spontaneous generation. 3. Louis Pasteur is credited with conclusively disproving the theory of spontaneous generation with his famous swan-neck flask experiment. He subsequently proposed that “life comes from life.” 4. The postulates of the cell theory was made possible through the invention of the microscope. 5. The postulates of the cell theory are: a. Cell is the basic unit of life b. All organisms are made up of cell c. Cell comes from pre-existing cell What I Can Do REFLECTIVE WRITING Write a short paragraph discussing why is it necessary for a student like you to understand and to look back on the history of the development of the cell theory. Make your answer brief and concise, express your answer using 5-10 sentences only. Assessment Multiple Choice. Choose the letter of the best answer. Write the chosen letter on a separate sheet of paper. 1. This term means life comes from non-life a. Abiotic b. Biotic c. Abiogenesis d. Biogenesis 2. Which of the following statements is NOT part of the cell theory? a. Cells are the basic unit of structure and function in all living things. b. All cells are produced from other cells. 13 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 c. Only animal cells are composed of cells. d. All living things are composed of cells 3. It is one way in which all living things on Earth are alike. a. All living things have hair b. All living things are made of cells and come from other cells c. The cells of all living things have chloroplast d. All living things can move 4. The first part of the cell theory states: “What happens in cell theory, stay in Cell Theory” a. True b. False c. Sometimes true d. Sometimes false 5. Why are microscopes important when studying most cells? a. Most cells are very large b. Most cells are very small c. Most cells move very quickly d. Most cells are dead 6. Which of the following scientists concluded that all ANIMALS are made up of cells? a. Rudolf Virchow b. Matthias Schleiden c. Robert Hooke d. Theodor Schwann 7. Which of the following is NOT one of the main components of the cell theory? a. cells must contain DNA b. all living things are made of cells c. cells can only come from other cells d. cells are the basic unit of life 8. Rudolph Virchow's observations helped to disprove was commonly held belief of the time? a. evolution b. the existence of molecules c. spontaneous generation d. atomic models 9. Which technology was essential for the development of the cell theory? a. Telescopes b. Antiseptics c. Microwaves d. Microscopes 10. Which of the following is a key difference between Needham's and Spallanzani's experiments testing the idea of spontaneous generation? a. Needham heated his broth while Spallanzani did not. b. Spallanzani heated his broth while Needham did not c. Needham sealed his flasks tightly while Spallanzani did not. 14 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 d. Spallanzani sealed his flasks tightly while Needham did not. 11. He discovered that all plants were made of cells, which contributed to the development of the cell theory: a. Anton van Leeuwenhoek b. Robert Hooke c. Theodor Schwann d. Matthias Schleiden 12. He advanced the cell theory with his conclusion that cells could only come from other cells: a. Anton van Leeuwenhoek b. Rudolph Virchow c. Theodor Schwann d. Robert Hooke 13. Which scientist disproved spontaneous generation of large organisms by showing maggots came from flies not from rotting meat? a. Redi b. Needham c. Spallanzani d. Pasteur 14. Who stated that cell comes from pre-existing cell? a. Matthias Schleiden b. Theodor Schwann c. Rudolf Virchow c. John Needham 15. Which scientist designed a special flask that allowed air in but kept microbes out and once and for all disproved spontaneous generation? a. Redi b. Needham c. Spallanzani d. Pasteur 15 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 Additional Activities Make a time line consisting of people and events who worked for the development of the cell theory. Use the template below in completing your timeline. 3 Points Exit Three concepts I learned: 1. ________________________________________________ 2. ________________________________________________ 3. ________________________________________________ Two real-life realizations after finishing the topic 1. _________________________________________________ 2. _________________________________________________ One most favorite part of the lesson 1. _________________________________________________ 16 Downloaded by Josh Delar ([email protected])  Downloaded by Josh Delar ([email protected]) 17 ASSESSMENT MATCHING TYPE WHAT I KNOW (POST-TEST) 1. C Pre-test 1. C 2. A 1. D 2. C 2. B 3. B 3. B 3. A 4. B 4. C 5. B 4. E 5. D 6. D 6. D 7. A 5. D 7. A 8. C 8. C 9. D 9. D 10. D 10. C 11. D 11. C 12. B 12. B 13. A 13. B 14. C 14. B 15. D 15. D Answer Key lOMoARcPSD|42657537  lOMoARcPSD|42657537 References: K. Zwier. "Aristotle on Spontaneous Generation." http://www.sju.edu/int/academics/cas/resources/gppc/pdf/Karen%20R.%20 Zwier.pdf E. Capanna. "Lazzaro Spallanzani: At the Roots of Modern Biology." Journal of Experimental Zoology 285 no. 3 (1999):178–196. R. Mancini, M. Nigro, G. Ippolito. "Lazzaro Spallanzani and His Refutation of the Theory of Spontaneous Generation." Le Infezioni in Medicina 15 no. 3 (2007):199– 206. R. Vallery-Radot. The Life of Pasteur, trans. R.L. Devonshire. New York: McClure, Phillips and Co, 1902, 1:142. https://courses.lumenlearning.com/microbiology/chapter/spontaneous- generation/ https://quizizz.com/admin/quiz/583d8fb488fa71303b831a1d/cell-theory https://www.gulfcoast.edu/current-students/academic-divisions/natural- sciiencess/biology-project/origin-life/documents/8-cell-theory-historical- timeline-activity-dow-answer-key.pdf https://www.henhudschools.org/cms/libNY01813707/Centricity/Domain/139 0/HW%2012%20-%20Cell%20Theory%201.pdf Carmelita M. Capco. (2003). Phoenix Science Series Biology, pages 154-156 18 Downloaded by Josh Delar ([email protected])  lOMoARcPSD|42657537 For inquiries or feedback, please write or call: Department of Education - Bureau of Learning Resources (DepEd-BLR) Ground Floor, Bonifacio Bldg., DepEd Complex Meralco Avenue, Pasig City, Philippines 1600 Telefax: (632) 8634-1072; 8634-1054; 8631-4985 Email Address: [email protected] * [email protected] Downloaded by Josh Delar ([email protected])