Environmental and Genetic Influences

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📚 Part 1: Multiple Choice

1. Two groups of genetically identical plants are grown. Group A receives more sunlight than Group B. Group A grows taller. This result most directly supports which conclusion?

Height is determined only by genes.

Environmental factors like light can change growth.

Sunlight changes the DNA sequence of the plants.

Taller plants always have different genes than shorter plants.

2. Scientists place siblings from the same family in different diets and observe changes in weight. Which type of influence does this experiment test?

Genetic influence only

Environmental influence only

Both genetic and environmental influences equally without testing

Random mutation rates

3. A trait appears in a population even when environmental conditions are varied widely and the trait remains constant. This pattern most likely indicates the trait is:

Strongly influenced by the environment

Likely controlled by genetic factors

Caused by recent mutations in every individual

Due to measurement error

4. In a common garden experiment, researchers grow individuals from different populations in the same environment. Which outcome supports a genetic explanation for differences observed in the wild?

Individuals become identical in all traits

Differences persist between populations

All individuals die from the new environment

New traits appear only after several generations

5. A population of rabbits shows darker fur in colder regions and lighter fur in warmer regions. Which explanation is an environmental influence?

Rabbits in cold regions have a gene for dark fur only

Temperature affects pigment production during development

Dark fur evolved millions of years ago and is unrelated

Lighter fur is a result of predators' choice

6. Two strains of bacteria differ in growth rate. Sequence analysis shows a mutation in one strain linked to faster metabolism. This evidence best supports:

An environmental cause for growth differences

A genetic cause for growth differences

That measurement error caused the difference

That both strains are identical genetically

7. A fish species raised in low-oxygen water develops larger gill surface area than the same species raised in high-oxygen water. What does this indicate?

Gill size is fixed by genes and cannot change

Gill development can respond to environmental conditions

Low oxygen caused new genes to appear instantly

Measurement of gill size is unrelated to oxygen

8. Identical twins show different heights as adults. Which piece of evidence would most strongly support environmental influence?

Both twins ate the same diet their whole lives

One twin experienced long-term illness during childhood

Both twins share the same DNA

Height is always 100% genetic

9. Which experimental design helps separate genetic from environmental causes of a trait?

Observing animals only in their natural habitats

Raising organisms from different parents in the same environment (common garden)