(M3) Multiple Choice. Write the letter of the correct answer on a separate sheet of paper.

1. Which of the following statement is TRUE of populations that are in Hardy-Weinberg equilibrium?
A. Mating is random.
B. Natural selection is occurring.
C. Organisms are constantly migrating.
D. The populations must be very small.

2.What mechanism of evolution occurs when allele frequencies change over generations due to random chance?
A. mutation
B. gene flow
C. genetic drift
D. natural selection

3. What is the frequency of homozygous dominant individuals if the recessive allele b occurs with a frequency of 0.8 in a population of crabs that is in Hardy-Weinberg equilibrium?
A. 0.8
B. 0.64
C. 0.32
D. 0.04

4. What is the main source of genetic variation among humans?
A. genetic drift
B. migration of humans
C. environmental effects
D. the reshuffling of alleles

5.In humans, babies that are born too small often difficult to survive while those that are too large are prone to experience difficulty at birth. Since babies at the extremes are less likely to survive, evolutionary pressures favor moderately sized babies. What type of selection is described in the given situation?
A. artificial
B. directional
C. disruptive
D. stabilizing