Ans: (E)
Question: What causes cell walls to relax?
Options:
- (A) exercise
- (B) sweating
- (C) adding heat
- (D) Energy
- (E) dilation
- (F) heat or cold
- (G) heat
- (H) Dehydration
CoT: Dilation occurs when cell walls relax. When oxygen level decreases, dilatation of the blood vessels occurs. Decreased oxygen levels cause blood vessels to dilate and cell walls to relax.

Ans: (H)
Question: What are viruses not?
Options:
- (A) self-copies
- (B) an object
- (C) HIV
- (D) humans
- (E) infectious
- (F) homogenous
- (G) dangerous
- (H) prokaryotes
CoT: Populations of viruses do not grow through cell division because they are not cells. Prokaryotes multiply by simple cell division, forming clones or exact copies of themselves. Viruses are not prokaryotes.

Ans: (D)
Question: Which of the following does not have an anterior and posterior end?
Options:
- (A) Adult mammals
- (B) Adult reptiles
- (C) Adult birds
- (D) Adult echinoderms
- (E) Earth orbiting the Sun
- (F) an erupting volcano
- (G) peachleaf willow
- (H) sensory neurons
CoT: Adult echinoderms have radial symmetry. Animals with radial symmetry lack an anterior and posterior end. Adult echinoderms lack an anterior and posterior end.

Ans: (E)
Question: Carbon in organic compounds are passed through the food web from what?
Options:
- (A) it helps plants in growing
- (B) Burning fuel and air
- (C) members of their own species
- (D) people to dogs
- (E) herbivores to carnivores
- (F) carnivores to plants
- (G) passenger pigeons
- (H) predators to prey
CoT: Energy is passed up a food chain or web from lower to higher trophic levels. Energy and carbon in organic compounds passed through food chain to herbivores and carnivores. Carbon in organic compounds are passed through the food web from herbivores to carnivores.