q: The two-chambered heart of some backboned aquatic animals is part of their:
Options:
- (A) aerobic capacity
- (B) three-chambered heart
- (C) biological diversity
- (D) it keeps an organism warm
- (E) the body's largest organ
- (F) circulatory system
- (G) salmon
- (H) swimming system
a: (F)... Explanation: Fish have a circulatory system with a two-chambered heart. Fish are backboned aquatic animals. Some backboned aquatic animals have a circulatory system with a two-chambered heart. That's why the answer is (F).

q: What involves interaction with ribosomes?
Options:
- (A) permineralization
- (B) oxidation reaction
- (C) It helps them survive
- (D) Translation of mRNA
- (E) flow of electrons
- (F) animal transport
- (G) resistance activities
- (H) allow growth
a: (D)... Explanation: Translation reads the genetic code in mRNA and makes a protein. Translation of mRNA into protein involves the interaction of the mRNA with ribosomes. Translation of mRNA involves interaction with ribosomes. That's why the answer is (D).

q: What lives in water that contains little or no salt?
Options:
- (A) animals
- (B) terrapins
- (C) a fish
- (D) Chlorophyll
- (E) bacteria
- (F) sharks
- (G) sodium
- (H) humans
a: (B)... Explanation: Freshwater biomes have water that contains little or no salt. Terrapins are freshwater turtles. Terrapins live in water that contains little or no salt. That's why the answer is (B).

q: Ethologists study how animals behave in animals'
Options:
- (A) Summer
- (B) state
- (C) Birds
- (D) life
- (E) seasons
- (F) health
- (G) homes
- (H) fields
a:
(G)... Explanation: Ethologists usually study how animals behave in their natural environment. Environments are animals homes. Ethologists usually study how animals behave in the animals' homes. That's why the answer is (G).