question... Where does the energy to evaporate perspiration come from?
Options:
- (A) heat produced
- (B) The Sun
- (C) goosebumps
- (D) electrical energy
- (E) kinetic force
- (F) body heat
- (G) heat energy
- (H) energy
answer... Evaporation of sweat uses energy, and the energy comes from body heat. Sweat glands pump perspiration through pores. Perspiration comes through pores and is evaporated by energy from body heat.
The answer is (F)

question... How are atolls built?
Options:
- (A) important habitats
- (B) By coral exoskeletons
- (C) by fish
- (D) with machines
- (E) by a type of eel
- (F) It used to be covered by water
- (G) The area was once underwater
- (H) reusing materials
answer... Many corals secrete an exoskeleton that builds up to become a coral reef. An atoll is the third type of reef. Atolls are built by corals secreting an exoskeleton.
The answer is (B)

question... What happens when muscular walls of arteries and veins contract?
Options:
- (A) connection
- (B) It expands
- (C) Dehydration
- (D) construction
- (E) forces
- (F) massive damage
- (G) constriction
- (H) contraction
answer...
Constriction occurs when the muscular walls of blood vessels contract. Arteries and veins are blood vessels. Constriction happens when the muscular walls of arteries and veins contract.
The answer is (G)