Ques and Ans: Mussels have what?
Options:
- (A) seaweed
- (B) arms
- (C) Energy
- (D) a shell
- (E) warmth
- (F) bacteria
- (G) Length
- (H) legs
(D)
Logic chain: Most mollusks have shells. Mussels are bivalve mollusks. Mussels have shells.

Ques and Ans: What can be determined by the average number of people per one unit of area?
Options:
- (A) hygeine
- (B) emissions
- (C) animals
- (D) growth
- (E) forces
- (F) health
- (G) education
- (H) people
(D)
Logic chain: Population density is the average number of individuals per unit of area or volume. Another measure of growth is population density. Growth of an area can be determined by the average number of people per unit of area.

Ques and Ans: Bottleneck effect can be a precursor to what?
Options:
- (A) massive damage
- (B) Climate change
- (C) Destroy bridges
- (D) Cambrian explosion
- (E) ground to shake
- (F) clams
- (G) soda
- (H) extinction
(H)
Logic chain: Bottleneck effect occurs when a population suddenly gets much smaller. Population size is the predictor of extinction probability. Bottleneck effect can be a precursor to extinction.

Ques and Ans: Evolution is a change in the genetic traits of living things over what?
Options:
- (A) universes
- (B) HIV
- (C) long
- (D) extinct organisms
- (E) dead things
- (F) time
- (G) H 2 O
- (H) years
(F)
Logic chain:
Evolution is a change in the characteristics of living things over time. Almost all physical characteristics are genetic traits, inherited from parents. Evolution is a change in the genetic traits of living things over time.