Question 1

Which of the following best describes a good scientific hypothesis?

Accepted Answer

It is a statement that can be tested and potentially falsified by experiments.

Question 2

In an experiment testing the effect of fertilizer on plant growth, which variable is the independent variable?

Accepted Answer

The amount of fertilizer applied to the plants.

Question 3

How does genetic diversity contribute to overall biodiversity in an ecosystem?

Accepted Answer

It increases the variety of traits within a species, allowing populations to adapt to changing environments.

Question 4

Which of the following best explains the greenhouse effect?

Accepted Answer

Greenhouse gases trap heat in the Earth's atmosphere, leading to an increase in global temperatures.

Question 5

During meiosis I in a cell with $$2n = 2$$, which of the following correctly identifies the relationship between homologous chromosomes and sister chromatids?

Accepted Answer

Homologous chromosomes pair up, each consisting of two sister chromatids, and are separated into different cells.

Question 6

The experiment with C. elegans grown with or without pathogens supports the changing environment hypothesis for sexual reproduction because:

Accepted Answer

Sexually reproducing populations adapted better to the presence of pathogens due to increased genetic variation.

Question 7

Why is meiosis necessary for sexual reproduction?

Accepted Answer

It reduces the chromosome number by half, ensuring offspring have the correct chromosome number after fertilization.

Question 8

In peas, the gene for tall (T) is dominant over short (t). If a heterozygous tall plant ($$Tt) is $$crossed with a homozygous short plant ($$tt$$), what is the expected phenotypic ratio of their offspring?

Accepted Answer

$$1$$ tall : $$1$$ short

Question 9

In rabbits, the gene for black fur (B) is dominant over white fur (b). If two heterozygous black-furred rabbits ($$Bb) $$are crossed, what is the probability of having a white-furred offspring?

Accepted Answer

$$\frac{1}{4}$$

Question 10

In fruit flies, the gene for red eyes (R) is dominant over white eyes (r). If a heterozygous red-eyed fly ($$Rr) is $$crossed with a white-eyed fly ($$rr$$), what is the expected genotype ratio of their offspring?

Accepted Answer

$$1 Rr$$ : $$1 rr$$

Question 11

In horses, the gene for brown coat color (B) is dominant over chestnut (b). If two heterozygous brown-coated horses ($$Bb) $$are crossed, what is the expected phenotypic ratio of their foals?

Accepted Answer

$$3$$ brown : $$1$$ chestnut

Question 12

A heterozygous black, short-furred guinea pig ($$BbLl) is $$crossed with a brown, long-furred guinea pig ($$bbll). $$Assuming independent assortment, which of the following is a possible phenotype among their offspring?

Accepted Answer

Black, long fur

Question 13

In fruit flies, the genes for wing shape (W/w) and eye color (E/e) are linked. If a $$WwEe$$ fly is crossed with a $$wwee$$ fly, and the $$WwEe$$ fly was produced from $$WWEE 	imes wwee$$ parents, what is the expected phenotype ratio of their offspring (assuming no crossing over)?

Accepted Answer

1 winged, red-eyed : 1 wingless, white-eyed

Question 14

Which scenario best illustrates the effect of multiple alleles creating a range of phenotypes?

Accepted Answer

Human blood types (A, B, AB, O) determined by three alleles at one gene locus.

Question 15

How does the phenotypic ratio in a cross exhibiting incomplete dominance differ from one with complete dominance?

Accepted Answer

The heterozygote displays an intermediate phenotype, resulting in a $$1:2:1$$ ratio.

Question 16

Why might genetically identical plants exhibit different phenotypes when grown in different environments?

Accepted Answer

Environmental factors such as light, water, and nutrients can influence gene expression.

Question 17

Which of the following best distinguishes pleiotropy from gene interaction?

Accepted Answer

Pleiotropy is when one gene affects multiple traits, while gene interaction involves multiple genes affecting a single trait.

Question 18

Traits governed by quantitative inheritance, such as human height or skin color, often show a bell curve distribution in a population because:

Accepted Answer

They are influenced by many genes, each contributing a small effect, resulting in continuous variation.

Question 19

A researcher wants to test the effect of temperature on the rate of enzyme activity. Which of the following is the best way to design this experiment?

Accepted Answer

Keep all variables constant except temperature, which is systematically varied, and measure enzyme activity as the dependent variable.

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