WGU C190 Biology Final Exam 2026 (500
Questions) – C190 – Cell Biology, Genetics &
Evolution Review – Western Governors
University
Section 1: Foundations of Biology and Chemistry of Life (Questions 1-15)
1. What is the difference between biotic and abiotic factors?
Answer: Biotic describes living organisms or matter that was once alive. Abiotic
describes non-living materials that have never been alive, such as water, rocks, or
sunlight.
Rationale: This is a fundamental classification in ecology used to define the
components of an ecosystem. Understanding this distinction helps in analyzing
how living and non-living parts interact.
2. What is the smallest unit of matter?
Answer: The atom is the basic unit of matter, consisting of a nucleus surrounded by
electrons.
Rationale: Atoms are the building blocks for all chemical elements. Everything
physical is made of atoms combined in various ways.
3. What is a molecule?
Answer: A molecule is a chemical structure formed by at least two atoms held
together by a chemical bond.
,Rationale: Molecules are the next level of organization above atoms. Water (H₂O)
and oxygen gas (O₂) are common examples.
4. What is a biological macromolecule?
Answer: Biological macromolecules are large molecules, often polymers, formed
when atoms bond together. The four main classes are carbohydrates, lipids,
proteins, and nucleic acids.
Rationale: These are the essential organic molecules for life. They make up the
structures and carry out the functions of cells.
5. What is the fundamental unit of life?
Answer: The cell is the smallest unit that displays all the characteristics of life.
Rationale: All living things are composed of one or more cells. Cells can carry out
all necessary life processes independently.
6. Define a population.
Answer: A population consists of all the individuals of the same species living and
interacting in a specific area.
Rationale: This ecological level focuses on one species in a defined location, such
as all the white-tailed deer in a particular forest.
7. Define a community.
Answer: A community includes all the different populations (all species) interacting
with each other within a specified area.
Rationale: This level encompasses the living components of an ecosystem,
including plants, animals, fungi, and microorganisms.
,8. Define an ecosystem.
Answer: An ecosystem consists of all the living (biotic) things in a particular area
together with the nonliving (abiotic) parts of that environment.
Rationale: This combines living organisms and their physical environment,
including factors like sunlight, soil, water, and temperature.
9. What is homeostasis?
Answer: Homeostasis is the ability of an organism to maintain a stable internal
environment.
Rationale: Examples include maintaining a constant body temperature, blood pH,
or glucose levels despite external changes.
10. What is evolution?
Answer: Evolution is the scientific theory that explains how and why life changes
over time through processes like natural selection and shared ancestry.
Rationale: Evolution is the unifying theory of all biology, explaining both the diversity
and unity of life.
11. What is natural selection?
Answer: Natural selection is the process in which individuals with certain inherited
traits tend to survive and reproduce at higher rates than other individuals because of
those traits.
Rationale: This leads to adaptation in populations over time. It requires variation,
heritability, and differential reproductive success.
, 12. What are the subatomic particles of an atom?
Answer: The three main subatomic particles are protons (positive charge), neutrons
(neutral charge), and electrons (negative charge).
Rationale: Protons and neutrons are in the nucleus; electrons orbit around the
nucleus in electron shells.
13. What is an ion?
Answer: An ion is an atom that has gained or lost an electron, giving it a positive or
negative electrical charge.
Rationale: Cations are positively charged (lost electrons); anions are negatively
charged (gained electrons). Ions are critical for nerve function and many chemical
reactions.
14. What is atomic number?
Answer: The atomic number is the number of protons in the nucleus of an atom,
which uniquely identifies an element.
Rationale: For a neutral atom, this also equals the number of electrons. Hydrogen
has atomic number 1; carbon has atomic number 6.
15. What is a covalent bond?
Answer: A covalent bond is a strong chemical bond formed when two atoms share
a pair of electrons.
Rationale: This is the primary bond holding atoms together within a molecule.
Covalent bonds can be single, double, or triple depending on how many electron
pairs are shared.
Questions) – C190 – Cell Biology, Genetics &
Evolution Review – Western Governors
University
Section 1: Foundations of Biology and Chemistry of Life (Questions 1-15)
1. What is the difference between biotic and abiotic factors?
Answer: Biotic describes living organisms or matter that was once alive. Abiotic
describes non-living materials that have never been alive, such as water, rocks, or
sunlight.
Rationale: This is a fundamental classification in ecology used to define the
components of an ecosystem. Understanding this distinction helps in analyzing
how living and non-living parts interact.
2. What is the smallest unit of matter?
Answer: The atom is the basic unit of matter, consisting of a nucleus surrounded by
electrons.
Rationale: Atoms are the building blocks for all chemical elements. Everything
physical is made of atoms combined in various ways.
3. What is a molecule?
Answer: A molecule is a chemical structure formed by at least two atoms held
together by a chemical bond.
,Rationale: Molecules are the next level of organization above atoms. Water (H₂O)
and oxygen gas (O₂) are common examples.
4. What is a biological macromolecule?
Answer: Biological macromolecules are large molecules, often polymers, formed
when atoms bond together. The four main classes are carbohydrates, lipids,
proteins, and nucleic acids.
Rationale: These are the essential organic molecules for life. They make up the
structures and carry out the functions of cells.
5. What is the fundamental unit of life?
Answer: The cell is the smallest unit that displays all the characteristics of life.
Rationale: All living things are composed of one or more cells. Cells can carry out
all necessary life processes independently.
6. Define a population.
Answer: A population consists of all the individuals of the same species living and
interacting in a specific area.
Rationale: This ecological level focuses on one species in a defined location, such
as all the white-tailed deer in a particular forest.
7. Define a community.
Answer: A community includes all the different populations (all species) interacting
with each other within a specified area.
Rationale: This level encompasses the living components of an ecosystem,
including plants, animals, fungi, and microorganisms.
,8. Define an ecosystem.
Answer: An ecosystem consists of all the living (biotic) things in a particular area
together with the nonliving (abiotic) parts of that environment.
Rationale: This combines living organisms and their physical environment,
including factors like sunlight, soil, water, and temperature.
9. What is homeostasis?
Answer: Homeostasis is the ability of an organism to maintain a stable internal
environment.
Rationale: Examples include maintaining a constant body temperature, blood pH,
or glucose levels despite external changes.
10. What is evolution?
Answer: Evolution is the scientific theory that explains how and why life changes
over time through processes like natural selection and shared ancestry.
Rationale: Evolution is the unifying theory of all biology, explaining both the diversity
and unity of life.
11. What is natural selection?
Answer: Natural selection is the process in which individuals with certain inherited
traits tend to survive and reproduce at higher rates than other individuals because of
those traits.
Rationale: This leads to adaptation in populations over time. It requires variation,
heritability, and differential reproductive success.
, 12. What are the subatomic particles of an atom?
Answer: The three main subatomic particles are protons (positive charge), neutrons
(neutral charge), and electrons (negative charge).
Rationale: Protons and neutrons are in the nucleus; electrons orbit around the
nucleus in electron shells.
13. What is an ion?
Answer: An ion is an atom that has gained or lost an electron, giving it a positive or
negative electrical charge.
Rationale: Cations are positively charged (lost electrons); anions are negatively
charged (gained electrons). Ions are critical for nerve function and many chemical
reactions.
14. What is atomic number?
Answer: The atomic number is the number of protons in the nucleus of an atom,
which uniquely identifies an element.
Rationale: For a neutral atom, this also equals the number of electrons. Hydrogen
has atomic number 1; carbon has atomic number 6.
15. What is a covalent bond?
Answer: A covalent bond is a strong chemical bond formed when two atoms share
a pair of electrons.
Rationale: This is the primary bond holding atoms together within a molecule.
Covalent bonds can be single, double, or triple depending on how many electron
pairs are shared.
