Grade 9 Science Quiz

The process that produces sex cells is meiosis.
Probability is most often written as a fraction or a percentage.
In meiosis, chromosomes are copied twice, and the nucleus divides once, producing four cells from a single cell.
Incomplete dominance describes a trait that is not completely dominant over another.

Genes are found on chromosomes.
Damage to the genetic material in skin cells can cause skin cancer.
A recessive trait reappears in the second generation after disappearing in the first.

Using a specific example of eye color, a brown eye (B) allele being dominant and a green eye (b) allele being recessive, this problem determines the possible phenotypes and genotypes of offspring when two parents with Bb and bb genotypes are crossed.

The diagram depicts the stages of mitosis, a type of cell division. Questions on this page ask for the correct matching of stages.

Nails grow from living cells in the nail root.
Skin color is determined by the chemical substance called melanin.
The skeletal system provides a frame to support and protect body parts.
A tissue is a group of similar cells that perform a common function.
A hair forms at the bottom of a tiny sac called a hair follicle.
Connective tissue joins, supports, and protects organs.
The two layers of skin are epidermis and dermis.
The lymphatic system returns leaked fluids to blood vessels and helps get rid of bacteria and viruses.

The digestive system is a series of tube-like organs.
Mechanical digestion involves breaking down large food molecules into smaller nutrients.
Teeth are important for mechanical digestion.
Premolars are well-suited for grinding food.
After several hours of digestion, food becomes a soupy mixture called chyme.
Saliva contains enzymes that initiate carbohydrate digestion.
The esophagus connects the pharynx to the stomach.
Bile breaks down fat droplets.
Pancreatic fluid neutralizes chyme.
The rectum is the final part of the large intestine.
Nephrons are microscopic filters in the kidneys that remove wastes from blood.
ADH signals the kidneys to take water from nephrons.
Bile is temporarily stored in the gallbladder.
Chemical and mechanical digestion processes occur in the digestive system.
Urinary system problems can include bacterial infections, kidney stones, and kidney disease.

Three key functions of the liver include breaking down fats, storing nutrients, and breaking down toxins.
The urinary system includes the kidneys, ureter, urinary bladder, and urethra.

The function of the menstrual cycle is to prepare the body for pregnancy.
The umbilical cord connects the embryo to the placenta.
Puberty usually occurs between ages 9 and 14.
The placenta provides oxygen and nutrients to the embryo.
Implantation is the embedding of the embryo into the uterine wall.
Wastes from the embryo are removed by the placenta.
Asexual reproduction results in offspring that are genetically identical to the parent.
The female reproductive organs called ovaries produce sex cells.
Semen is the mixture of sperm and fluids from the prostate gland.
Ovulation involves releasing an egg from an ovary.
The fallopian tube carries the egg.
The vagina connects externally to the uterine area.
The menstrual cycle typically lasts 28 days.
Menstruation is the monthly discharge of blood and tissue from the uterus.

Three groups of mammals are monotreme, marsupial, and placental.
Reproductive system problems such as sexually transmitted diseases (STDs), cancer, and infertility.
Testes produce sperm and male sex hormones like testosterone.
Ovaries produce eggs and female hormones like estrogen and progesterone.

Acid precipitation is rain with high acid concentrations.
Oxidation is a chemical reaction where oxygen combines with elements.
Examples of chemical weathering agents are water, air, and weak acids.
Weathering of rock can result in erosion, wearing away rock and transporting fragments.
Differential weathering occurs when less resistant rock erodes faster than harder rock.
The arrangement of soil particles is referred to as soil structure.

The development of a river is influenced by factors like climate, gradient, and the load or material carried.
River development can be characterized as stages, including youthful, mature, old, and rejuvenated rivers.
Tributaries are smaller streams flowing into a larger stream.

Stars are huge, hot balls of gas.
The spectrum is a band of colors produced when white light passes through a prism.
Astronomers use spectrographs to analyze stars' spectra.
A star's spectrum is an absorption spectrum.
A light-year measures the distance light travels in a year.
Parallax is the apparent shift in a star's position.
A red giant forms when a star expands when it uses all its hydrogen.
A white dwarf is a leftover star core.
A supernova is a star explosion.
A neutron star forms when particles in a collapsing star become neutrons.
A pulsar is a spinning neutron star.
A black hole is so massive that light cannot escape its gravity.
Galaxies are groups of stars, dust, and gas.

Choices for Multiple-choice Questions: Mitosis, Meiosis, Heredity, Probability, Fraction, Percentage, Environmental factors, Incomplete dominance, Recessive, Chromosome, Genes, Allele, Sex cells, Tissue, Organism, Organ, Nail root, Epidermis, Melanin, Skin cancer, Collagen, Keratin, Urinary system, Skeletal system, Digestive tract
Other Biology concepts: Menstrual cycle, Identical twins, Sperms, Fertilization, Hormones, Ovaries, Embryo, Placenta, Uterus, Ovulation, Vagina, Fallopian tubes, STDs, Cancer.