Correct answer: A

The correct answer is Heritable traits that improve reproductive success become more common over generations.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: Natural selection changes populations when inherited variation affects survival or reproduction in a particular environment.
3. Connect structure and function: The correct answer is Heritable traits that improve reproductive success become more common over generations.

Correct answer: B

The correct answer is A change in allele frequencies caused by random sampling, especially in small populations.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: Drift is random rather than directed and can have a strong effect when populations are small.
3. Connect structure and function: The correct answer is A change in allele frequencies caused by random sampling, especially in small populations.

Correct answer: C

The correct answer is Reproductive isolation that prevents gene flow between populations.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: When populations no longer exchange genes and diverge over time, they may become separate species.
3. Connect structure and function: The correct answer is Reproductive isolation that prevents gene flow between populations.

Correct answer: D

The correct answer is Common ancestry despite different current functions.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: Homologous structures share an underlying developmental pattern inherited from a common ancestor.
3. Connect structure and function: The correct answer is Common ancestry despite different current functions.

Correct answer: A

The correct answer is Allele and genotype frequencies in a population that is not evolving under specified conditions.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: The model provides a baseline for detecting evolutionary change when assumptions such as random mating and no selection are considered.
3. Connect structure and function: The correct answer is Allele and genotype frequencies in a population that is not evolving under specified conditions.

Correct answer: B

The correct answer is The largest population an environment can sustainably support.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: Resource availability, competition, predation, and other limiting factors influence carrying capacity.
3. Connect structure and function: The correct answer is The largest population an environment can sustainably support.

Correct answer: C

The correct answer is Energy generally decreases at higher trophic levels.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: Much energy is lost as heat and metabolism between trophic levels, so less is available to higher consumers.
3. Connect structure and function: The correct answer is Energy generally decreases at higher trophic levels.

Correct answer: D

The correct answer is It is exchanged among the atmosphere, organisms, oceans, and rocks through processes such as photosynthesis and respiration.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: Carbon moves through multiple reservoirs and processes, including photosynthesis, respiration, decomposition, and combustion.
3. Connect structure and function: The correct answer is It is exchanged among the atmosphere, organisms, oceans, and rocks through processes such as photosynthesis and respiration.

Correct answer: A

The correct answer is A relationship in which both interacting species benefit.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: Mutualism is one type of symbiosis and can improve access to resources, protection, or reproduction for both partners.
3. Connect structure and function: The correct answer is A relationship in which both interacting species benefit.

Correct answer: B

The correct answer is Variety can provide alternative functions and responses when conditions change.

1. Identify the biology concept: Determine whether the question concerns cells, molecules, genetics, evolution, ecology, physiology, or experimental design.
2. Apply the biological principle: Greater diversity can make ecosystems more capable of maintaining functions after disturbance.
3. Connect structure and function: The correct answer is Variety can provide alternative functions and responses when conditions change.