Ques:[What do trees release during the day but not at night?
Options:
- (A) Energy
- (B) water
- (C) He
- (D) Ce
- (E) chemicals
- (F) Energy.
- (G) heat
- (H) oxygen]
Ans:[Plants release oxygen during the day but not during the night. All plants are trees. Trees release oxygen during the day but not at night.
(H)]

Ques:[What happens when cell walls relax?
Options:
- (A) evaporation
- (B) permineralization
- (C) preventing heat transfer
- (D) allow growth
- (E) it keeps an organism warm
- (F) air cools
- (G) Cell walls expand
- (H) heat produced]
Ans:[Dilation occurs when cell walls relax. Blood flow is improved by vitamin E and it causes blood vessels to dilate or expand. When cell walls relax, they expand.
(G)]

Ques:[_ allow water to penetrate the soil.
Options:
- (A) crawfish burrows
- (B) major threat to health
- (C) Deposition
- (D) bending light rays
- (E) earthworm homes
- (F) Exfoliation
- (G) termite burrows
- (H) Earthworm burrows]
Ans:[Earthworm burrows help aerate soil, which is also good for plants. Aeration breaks up the soil and allows water to penetrate. Earthworm burrows allow water to penetrate the soil, which is good for plants.
(H)]

Ques:[Ethologists study how animals behave in animals'
Options:
- (A) Summer
- (B) state
- (C) Birds
- (D) life
- (E) seasons
- (F) health
- (G) homes
- (H) fields]
Ans:
[Ethologists usually study how animals behave in their natural environment. Environments are animals homes. Ethologists usually study how animals behave in the animals' homes.
(G)]