Year 10 Science Task 4 Notification PDF

A picture containing drawing Description automatically generated **Year 10 Science** **Task 4 Notification** **Topics included** **Units** **Checklist items:** (see page 2 for details) *10.3 Genetics and Biotechnology* *Checklist \# 1-5, 9-17, 21* *10.4 Chemical Reactions* *Checklist \# 1-4...

A picture containing drawing Description automatically generated **Year 10 Science** **Task 4 Notification** **Topics included** **Units** **Checklist items:** (see page 2 for details) *10.3 Genetics and Biotechnology* *Checklist \# 1-5, 9-17, 21* *10.4 Chemical Reactions* *Checklist \# 1-4, 7-12, 15-20.* *Balancing given chemical equations will also be assessed.* *10.5 Disease* *Checklist \# 1-10, 12-19* *10.6 Cosmology* *Checklist \# 1-8,10,11* **Date of task** Term 4 Week 3 -- assessment block **Time allocated** 90 minutes + 5 minutes reading time **Nature of task** Written task including multiple choice and free response questions. No practical component. **Weighting** 35% of yearly assessment (20% Knowledge and Understanding + 15% Working Scientifically Skills) **Other Information** Please bring a blue or black pen, a sharp pencil and eraser, a ruler and a calculator. Arrangements have been made for students with approved Disability Provisions. If you are one of these students and would **[not]** like to use these provisions for this task, you will need to email Learning Support within 3 days of receiving this notification. **Relevant Working Scientifically Skills** - **Science skill:** Identify the independent, dependent and controlled (constant) variables of an experiment. - **Science skill:** Write an aim, hypothesis and conclusion for an investigation. - **Science skill:** Identify appropriate materials (equipment/chemicals) to use in an investigation. - **Science skill:** Conduct a risk assessment for an investigation. - **Science skill:** Write a method for an investigation. - **Science skill:** Follow a given method to obtain results in a first-hand investigation. - **Science skill:** Make accurate measurements using correct units. - **Science skill:** Construct tables to summarise data and calculate averages from a set of results. - **Science skill:** Interpret column graphs, histograms, bar graphs, line graphs and pie graphs. - **Science skill:** Hand draw graphs. - **Science skill:** Evaluate the reliability, validity and accuracy of an investigation. - **Science skill:** Apply the scientific method. **Topic Checklists 2024** **10.3 Genetics and Biotechnology** **DNA and Inheritance** 1. Define chromosome and DNA. - Chromosome: long thread like structures made of DNA that hold genetic information for survival. - DNA: deoxyribonucleic acid; A polymer found in the nucleus of eukaryotic cells and cytoplasm of prokaryotic cells. 2. Recall the structure of DNA including: a. its shape as a double helix. b. the presence of a sugar-phosphate backbone. c. complementary base pairing by nitrogenous bases-\> adenine, guanine, cytosine, thymine d. the concept of nucleotides-\> deoxyribose sugar, phosphate, nucleotide base. e. Hydrogen bonds between complementary bases. 3. Briefly describe the process by which DNA replicates and explain the importance of accurate replication. \- DNA replication happens in the nucleus before cell division. The result is a polynucleotide chain with half of the original sequence. \- The two strands are separated as the hydrogen bonds between the bases breaks. \- The exposed nucleotides are attracted to the free complementary bases. \- The new pairs are bonded with DNA polymerase enzyme. 4\. Define "mutation" and describe: a. some of the effects of mutations. b. environmental causes of mutations (e.g. cigarette smoke, UV and nuclear radiation). \- A permanent change in the base sequence of DNA caused by mutagens or malfunctions during DNA replication. \- Point Mutation: A base sequence is changed \- Frameshift Mutation: A base is added or deleted. \- Mutation can have no effects, advantageous effects, disadvantageous effects. \- Environmental causes: Radiation: Cigarette smoke, UV radiation; Chemicals: Carcinogens, Processed foods; Infectious agents: Bacteria, Viruses. 5\. Recognise that many characteristics of an organism are inherited. ~~6. **Skill:** Complete a survey of family members observing physical traits (eg eye colour, tongue rolling, handedness).~~ ~~7. Recall the terms: sexual reproduction, gamete (REVISION).~~ ~~8. Recall that mitosis and meiosis involve the replication and movement of chromosomes and that meiosis involves the halving of chromosome number.~~ 9\. Outline Mendel's experiments and the inheritance of factors. \- Mendel crossbred red and white pea plants. \- First generation: Red plants \- Second generation: Red and white plants. \- Crosspollinated plants based on different features to make discoveries on how traits are inherited. -7 characteristics were tested. 10\. Define gene and allele. -Gene: A small section of DNA that codes for a specific protein to produce characteristics. -Allele: Variations of genes (dominant and recessive) 11\. Explore Mendel's results in terms of dominant and recessive genes. -Law of segregation: One hereditary factor from each parent. -Law of independent assortment: Different traits have equal opportunity of occurring together. -Law of dominance: Offspring will inherit dominant characteristics, unless both recessive factors are inherited. **12. Skill:** Draw and interpret Punnett squares. 13\. **Skill:** Draw and interpret family pedigrees for an observable trait. **Biotechnology** 14\. Define biotechnology and give some examples of its everyday uses. \- The use of an organism to make or change a product to be of service to humans. 15\. Describe recombinant DNA technology and give an example of where it is used (e.g., insulin production). \- Combining DNA from different organisms to produce desired genetic traits. \- Insulin gene is isolated. -Inserted into the plasmid acts as a vector \- Introduced to the bacteria, bacteria that successfully take up the plasmid are selected by antibiotic resistant markers. \- Cultured in large fermentation tanks where they grow and reproduce, producing more insulin protein. \- Insulin protein is extracted and used for medical purposes. 16\. **Research:** Discuss the development of genetically modified organisms (GMO), including plants (especially crops) and animals. \- Genetically modified organisms are organisms whose genes have been altered, either by adding agents form other organisms, or have been turn off/ deleted. \- GMO's reduce pesticides. Enhance food quality, form pharmaceuticals, increase agricultural productivity. \- Crops: herbicide and pest resistance, nutritional advancement \- Animals: Increased growth, disease resistance, improved production quality. 17\. Discuss the Human Genome Project and its importance in diagnosing and treating hereditary diseases and conditions. \- The human genome project is an international research project started in 1990 and ended in 2003 where scientists from all over the world collaborated to determine the base sequence pairs of the genome of a man and a woman. -Found the order of the base pair for all 46 chromosomes. ~~18. Distinguish between embryonic stem cells and adult stem cells and discuss their possible uses in research, diagnosis, and treatment.~~ ~~19. Examine the varied uses of cloning, such as in therapeutic cloning and cloning of whole organisms (e.g., Dolly the sheep).~~ ~~20. Investigate the role of technological development in advancing biological understanding.~~ 21\. **Debate or extended response**: Discuss the benefits, problems and ethics of using biotechnology. **10.4 Chemical Reactions** **Organisation and historical development of the Periodic Table** 1. Recall how to use the Periodic Table to determine the following: name and symbols for elements, their atomic number, atomic mass and electron configuration. - Atomic number: Number of protons - Atomic Mass: Number of protons + Number of neutrons - Electron configuration: In energy levels around the nucleus. 2. Recall how to use atomic number and mass number to determine the number of neutrons. - Atomic mass- Atomic Number= Number of Neutrons 3. Recall that patterns of nuclear structure, electron configuration and valency can be obtained from the periodic table. - Groups: Horizontal rows in which depict the valence electrons/charge of the elements in each group. - Periods: Vertical columns which show the number of shells for all the elements in each period. 4. Describe some trends in physical and chemical properties of elements, as they move across the period or down the group. - All elements in each group have the same chemical properties as they take part in the same reactions since, they need to lose or gain the same number of electrons. - Metals: Reactivity increases as you move down the group as the number of shells increases weakening the force of attraction between the nucleus and valence electron making it easy for the electrons to leave. - Non-metals: Reactivity decreases as you move down the group as the number of shells increasing so the forces between the nuclei and valence electrons decrease making it hard to attract electrons. - Non-metals: State of matter changes from gas to solid as you move down the group. 5. ~~**Practical:** Plan and conduct an experiment to investigate the reactivity of group 2 metals.~~ 6. ~~Describe the role of Mendeleev in the development of the Periodic Table.~~ **Chemical Formulae** 7. Distinguish between covalent and ionic compounds in terms of how they are formed. - Ionic compounds: Held together by ionic bonds which is the electrostatic force of attraction between oppositely charge particles of metal and non-metal atoms, in order to become stable. - Covalent compounds: Held together by covalent bonds which is when electrons are shared between non-metal atoms in order to gain stability. 8. Recall how to determine valencies of simple ions from the periodic table. - Group number 9. Learn the valencies for some common polyatomic ions. - NH4: 1+ - NH3: 1- - OH: 1- - C2H3O2: 1- - HCO3: 1- - NO3:1- - NO2:1- - CO3:2- - SO4:2- - SO3:2- - PO4: 3- - KO3: 3- 10. Recall that a salt is a compound consisting of a metal ion and a non-metal ion or radical (polyatomic ion). 11. Name ionic and covalent compounds given their chemical formula and write their chemical formulae given their names. **Chemical Reactions and Equations** 12. Identify that in a chemical reaction, atoms are not created or destroyed but are rearranged to form new substances. 13. ~~**Practical:** Conduct an investigation to demonstrate the Law of Conservation of Mass.~~ 14. ~~**Practical:** Conduct investigations to identify the reactants and products of the following types of chemical reactions:~~ - ~~combination~~ - ~~decomposition~~ - ~~combustion~~ - ~~precipitation~~ - ~~corrosion~~ 15. **Skill:** Construct word equations to represent reactions encountered throughout the topic including precipitation, combination, combustion, decomposition and corrosion reactions. - Precipitation: Soluble Salt + Soluble Salt Insoluble Salt + Soluble Salt - Corrosion: Metal + Oxygen Metal Oxide - Combustion: Metal + Oxygen Metal Oxide, Hydrocarbons + Oxygen Carbon dioxide + Water - Decomposition: XY X + Y - Combination: X+YXY **Radioactivity** 16. Define isotopes as forms of elements differing only in the number of neutrons and radioisotopes as isotopes which emit radioactivity as they decay to a more stable form. 17. Define what is meant by the half-life of a radioactive isotope. - Half-life: The amount of time taken for a radioactive nuclei atom to reduce to half its initial size in a sample. - The amount of time taken for the count rate to drop to half its initial level in a radioactive atom nuclei, in a sample. 18. Identify that natural radioactivity arises from the decay of nuclei in atoms, releasing particles and energy. 19. Contrast α, β and γ radiation in terms of structure and properties. - Alpha: A particle made of two neutrons and two protons. It has a high ionising power and very short range in air of approximately 5 cm. It can be stopped by paper and skin. - Beta: When in the nucleus, a neutron turns into a proton and electron. The electron shoots out of the nucleus. It has a low ionising power and short range in air of approximately 1 m. It can be stopped by aluminium. - Gamma: An electromagnetic wave that is released out of the nucleus. It has a very low ionising power and long range in air of \> 1km. It can be stopped by a thick layer of lead or concrete. 20. Evaluate the benefits and problems associated with medical and industrial uses of radioisotopes. - Benefits: Medicine: Cobalt-60 is used in cancer treatments. Radiotherapy penetrates the body killing cancer cells in the process. - Industrial: Caesium-137 is used for thickness gauging. Beta-2 emitters penetrate through the system being analysed. - Problems: Medicine: Radiotherapy can damage molecules inside and outside cells, disrupting their function, it can cause mutation leading to diseases such as leukaemia. - Industrial: Using radioisotopes means the waste produced is also radioactive. These radioisotopes have very long half-life's, therefore the waste needs to be stored carefully for a very long time. **New Materials** 21. ~~Research the production of a new material produced from chemical reactions and analyse how scientific research is influenced by social, ethical and environmental considerations.~~ **10.5 Disease** **What is disease?** 1. Define disease as an impairment of normal body function. 2. Classify diseases as infectious or non-infectious diseases and distinguish between the two. - Infectious diseases are diseases caused by pathogens. They can be transmitted from one person to another through various ways. - Non-infectious diseases are not caused by pathogens. They aren't transmitted from one person to another. They can be genetical, environmental and nutritional. **Infectious disease** 3. Describe pathogens as disease-causing agents. 4. Distinguish between the following groups of pathogens, outline their features, and give an example of a disease caused by: a. Bacteria - Single celled organisms that are small (0.01 micrometers) and reproduce independently. They require warm, moist conditions with access to food. They can cause inflammation in the body and release toxins. - Eg: Salmonella: - Caused by: Salmonella bacterium. - Spread through: Undercooked, raw food. - Symptoms: Diarrhea and vomiting. - Treatment: Antibiotics. - Precautions: Properly cooked food. b. Viruses - DNA/RNA in protein capsules, that are also smaller than bacteria (electron microscope) and require a host cell to grow in. They use the cells mechanism to grow and reproduce and destroy the cell as they burst out of it. Viruses cause inflammation and fever. - Eg: Covid-19: - Caused by: SarCov-2 - Spread through: Direct contact droplets, coughing, sneezing. - Symptoms: The virus affects the lining of the upper respiratory tract and moves to the lungs causing pneumonia in severe cases. Fever, Fatigue - Treatment: Medicines for symptoms, oxygen cylinders in severe cases. - Precautions: Social distancing, vaccination, masks c. Protozoa - Single celled organisms that divide independently. - Eg: Malaria - Caused by: Genus Plasmodium - Spread through: Anopheles Mosquito Vector transmission. - Symptoms: Fever and chills - Treatment: Anti-malarial drugs - Precautions: Mosquito nets, long sleeves d. Fungi - Unicellular (microscopic) or multicellular (not microscopic) organisms that grown in warm moist conditions with access to food. They are saprophytic. Their enzymes move into the surroundings and dissolve their food which is then absorbed by the fungi. - Eg: Candida - Caused by: Candida Albicans - Spread through: When antibiotics are taken and leave the body through the genital it could leave fungi behind to flourish. Affects skin, genitals, and mouth. - Symptoms: Inflammation and Itchiness - Treatment: Anti-fungal medicine - Precautions: Taking probiotics after antibiotics. e. Macroparasites - Invade and live in a host organism, competing for nutrients, leading to malnutrition and tissue damage. They disrupt the host's functions and affect their health. (worms and arthropods). 5. Describe some ways that infectious diseases can be transmitted including direct, indirect contact (including air droplets) and vector transmission. - Direct contact: The spread of a disease through physical contact between an infected person and a non-infected person Touching, kissing sneezing. - Indirect contact: The spread of a disease when an infected person touches objects contaminating them. These contaminated objects are known as fomite air and droplets. - Vehicle Transmission: Spread of a disease through contaminated air, water, and food. - Vector Transmission: Spread of a disease through animals that carry the disease. The animal could go through a part of its life as a vector, or not be affected at all. It carries the disease from an infected person to a non-infected person Mosquitos. 6. ~~**Practical:** Model the transmission of an infectious disease.~~ 7. Identify that the conditions needed to grow bacteria and fungi are warmth, moisture and a nutrients. 8. ~~**Practical:** Formulate a hypothesis to investigate where bacteria and fungi might be found and apply sterile techniques to test the hypothesis.~~ 9. **Explain the importance of sterile techniques to validity and minimizing risks when carrying out first hand investigations involving bacteria and fungi.** - Sterile Techniques: Only the bacteria and fungi being tested are present on the agar plate. This can be done through opening the lid at an angle and only when necessary. - Valid: The agar contains only what you want to experiment and no other contaminations that could disturb the results. - Safe: Washing your hands before and after touching the agar plate ensures no bacteria or fungi gets on your hand. Prevents cross-contamination. 10. Outline one plant and one animal disease of agricultural importance, including the type of pathogen, symptoms, and management. - Animal: Foot and Mouth Disease: Caused by a virus known as apthovirus. It is a highly contagious disease resulting in ulcers and blisters on the hooves, and mouths of cattles. It is so contagious that any animal affected must be destroyed and their carcass's having to be burnt. Hence, it had major economic impacts on the farming industry. - Plant: Myrtle Rust: A fungal disease caused by Austropuccinia that only affects plants from the myrtle family such as eucalyptus. It results in yellow spores forming on the leaves of the plant that results in stunted growth. The leaves infected must either be cut off or the plant must be sprayed with anti-fungal sprays. This disease has vast agricultural impacts. 11. ~~**Research** one infectious disease in humans, including the cause, symptoms, mode of transmission, preventative measures and treatment.~~ 12. **Describe antibiotics as medicines which kill bacteria.** 13. Distinguish between the term's epidemic and pandemic. - **Endemic: Typical rate at which a disease occurs in a certain population.** - **Epidemic: An epidemic is when the number of cases for an infectious or non-infectious disease rises significantly over normally expected levels, in a specific geographical area over a given period.** - **Pandemic: A pandemic is when the number of cases for a disease rises over the endemic levels across many countries/continents. It is typically a new-infectious disease for which people don't have immunity yet.** **Human defence against disease** 14. **Outline the roles of the first, second and third lines of defence, and distinguish between non-specific and specific defences.** - **First line of defenceNatural barriers Non-specific immunity** - **Second line of defence Innate immunity Non-specific immunity** - **Third line of defence Humoral immune responseSpecific immunity** 15. **Describe some ways that the first line of defence, including skin, stomach acid and tears prevent entry of pathogens.** - **Skin: The skin produces antimicrobial sweat that is low in pH and acts as a complete physical barrier against pathogens.** - **Stomach acid: The hydrochloric acid in the stomach has a low, acidic pH and hence, it destroys any bacteria or virus that were ingested with food before it can get to the intestines.** - **Tears: Tears contain lysozymes that help to wash away any and neutralise pathogens that enter the eye.** - **Trachea and Bronchi: Mucus traps any pathogens that enter the lungs and cilia, which are hair-like structures sweep the mucus up to the mouth.** - **Saliva: Saliva contains enzymes such as amylase and lysozymes that breakdown food and neutralise pathogens before they can enter the body acting as an additional barrier.** 16. **Outline the role of phagocytes and inflammation in the second line of defence.** - **Phagocytosis: Phagocytes are a type of white blood cells that destroy pathogens through the process of phagocytosis. When they come in contact with an antigen (any substance (could be a protein virus or a toxin Bacteria) that triggers an immune response) , they engulf it, form their membrane around it, and release enzymes that breakdown the pathogens.** - **Inflammation: Caused by chemical signals called histamines that are sent to the brain, to increase blood-flow in the area where the pathogens detected. Increase blood flow results in more phagocytes reaching the pathogens and destroying it. The increased blood flow in a certain area causes, redness and swelling in that area known as inflammation.** - **Fever: The body releases chemical signals to the part of the brain known as hypothalamus that is responsible for controlling body temperature. It raises the body temperature, making it unfit for enzymes, pathogens to survive.** 17. Outline the role of B cells in the third line of defence, including their specificity and their role in production of antibodies and memory cells. - **When an antigen is detected in the body, the B cells have unique receptors that bind to specific antigens. (B cells are produced in the bone marrow)** - **B cells divide into Plasma B cells and Memory B cells.** - **Primary response: Plasma B cells create antibodies (a protein produced by Plasma B cells) for the antigens, clumping them together and destroying them (neutralise the antigen, inactivating them) or signalling for phagocytes to do so. This process may take a few days and cause inflammation and fever.** - **Secondary response: If the pathogen were to re-enter the body, the memory cells would divide into Plasma B cells. They remember the antibody for the specific antigen and produce it if the pathogen re-enters. This process is a lot faster than the first time an antigen enters the body.** 18. Discuss the role of immunisation in disease prevention. - **The process by which a person becomes protected from a disease through vaccination.** - **Vaccination is the process by which a vaccine is introduced to the body to protect it against a specific disease.** - **Vaccine: A preparation that is used to stimulate a body's immune response against diseases.** - **Herd Immunity: High vaccination coverage in a population for protection against a certain disease and hence, end up protecting the people who are unable to take vaccines. It reduces the overall spread of pathogens.** **Non-infectious disease.** 19. Classify non-infectious diseases as genetic, environmental and nutritional and give examples of each. - Genetics: Diseases passed on through generations, in a family. - Eg: Cystic Fibrosis. - Caused By: When both parents carry recessive mutations of CFTR regulator genes. - Symptoms: Excess production of thick mucus, Sodium chloride distribution among cells is disrupted, damaging various organs. - Treatment: No specific treatment, Team of medical professionals create plans specific to each case, antibiotics, airway clearance, lung transplant. - Environmental: Caused by human interaction with their surrounding environment for a long time. - Eg: Melanoma - Caused by: Exposure to UV rays, genetics, immune system deficiencies. - Symptoms: Abnormal growth, moles of different colors and sizes. - Treatment: surgical removal of abnormal growth, and the surrounding skin, removal of lymph nodes, immunotherapy, radiation therapy - Precautions: Wearing SPF sunscreen, long sleeves, precautions from a young age. - Nutritional: Caused by deficiencies in diets. - Eg: Scurvy - Caused by: Lack of Vitamin C in the diet. - Symptoms: Fatigue, joint paint, muscle pain, bleeding gums, falling off teeth. - Treatment: Eating citrus fruits rich in vitamin C, taking vitamin C supplements, eating potatoes, broccoli and strawberries. - Precautions: Eating a balanced diet filled with Vitamin C rich food. 20. ~~**Research** one non-infectious disease, including the cause and any preventative measures.~~ **10.6 Cosmology** **Features of the Universe** 1. Identify that all objects exert a force of gravity on all other objects in the universe. 2. Distinguish between the different components (galaxies, stars, solar systems and nebulae) of the universe. Galaxies: A massive group of stars, dust gas, stellar remnants and dark matter, bound together by gravity. Stars: A colossal mass of gas and dust that is luminous and self sufficient. It drives its energy from its internal energy sources. Nebula: Interstellar nurseries made of gas and dust produced by supernova. It is where a star is born. Solar systems: A system of planets, stars, and moons that is bound together by a gravitational field. 3. Identify the different units of stellar distances (light years, astronomical units) *~~(Extension: parsecs).~~* *Astronomical Units: The average distance between the sun and the earth. It is used to measure distances within the earth.* *1 astronomical unit= 1.49 x 10\^8km* *Light years: The distance travelled by light within one year. It is used to measure distances beyond the solar system.* *1 light year = 9.46 x 10\^12 km* 4. **Skill:** Convert distances of light years to metres (and vice versa). 5. Describe nuclear fusion as the source of energy in the stars. The process by which atomic nuclei under extreme pressure and temperature fuses to form denser, heavier elements , releasing immense amount of energy. It is the source of energy in the star. 6. Describe the life cycle of stars, including a description of main sequence, red giants, white dwarfs, neutron stars and black holes. Nebula: Gravity pulls on the nebula closer making it hot and dense. Protostar: The particles collide and slide by each other, creating friction. This emits light. The hydrogen nuclei gain enough energy to fuse into a helium nuclei. This process is known as nuclear fusion. Main Sequence Star: The nuclear fusion releases thermal energy causing the star to expand. This is the most stable point in a star's life as the expansive forces= the gravitational pull. Stars the same size as the sun: Red giant: The star cools as it expands due to fusion and hence, appears redder. It is brighter than a main sequence star. White Dwarf: As the hydrogen depletes, the fusion stops. The gravitational forces\> expansive forces causing the star to collapse inwards. The outer layers of the star are expelled leaving a hot dense core known as the white dwarf. It is extremely bright due to the energy condensed into a small area. Black Dwarf: All the energy is emitted into the surroundings. The star becomes dimmer and turns brown/black becoming a black dwarf. Stars bigger than the size of the sun: Red supergiant: Fusion of the nuclei to the size of iron causes the star to get denser. When it runs out of fuel the core is so heavy that the gravitational forces pull the outer layer of the star towards the centre. Supernova: Shockwaves cause a collapse dispersing elements heavier than iron produced into the surroundings. Neutron Stars: Collapse from a neutron star, the remaining dense core of the star. Blackhole: Bigger stars form blackholes where gravity is so high that even light can't escape. 7. **Skill:** Draw the life cycle of a main sequence star of a similar size to our Sun. 8. Relate colours, brightness and absolute magnitude of stars to their age, size and distance from the Earth. Colour and age: The colour of the star determines its age as a newer star would be on the blue side of the spectrum as it has a lot of hydrogen fuel to burn and therefore it fuses and gives out energy, so the star is bright and high in temperature. But as the hydrogen burns out the star cools down and becomes dimmer and hence, is on the red side of the spectrum. Brightness and size: The bigger the star the brighter it is. Absolute magnitude and distance from the Earth: The closer to the Earth it is the more the magnitude. 9. ~~**Practical:** Conduct flame tests to help understand the colour of stars.~~ 10. Describe the Hertzsprung-Russell diagram. A Hertzsprung-Russell Diagram shows the relationship between the luminosity and temperature of a star. Blue stars are hotter and brighter while red stars are colder and dimmer. The trend line is the main sequence stars. Red giants, supergiants and white dwarfs are outliers. 11. **Skill:** Interpret a Hertzsprung-Russell graph of stars. 12. ~~**Research:** Describe two different technological developments that have enabled us to find out about the features and structures in the universe.~~