(question). Biomass is the total mass of living things at each what?
Options:
- (A) trophic level
- (B) important habitats
- (C) Energy.
- (D) food and shelter
- (E) Power plants
- (F) animals
- (G) body water
- (H) heat energy
(answer). Biomass is the total mass of organisms at a trophic level. Most living things are called organisms. Biomass is the total mass of living things at a trophic level.
The answer is (A)


(question). What affects the respiratory and circulatory systems in the body?
Options:
- (A) HIV
- (B) sulfur
- (C) smog
- (D) stress
- (E) fever
- (F) sweat
- (G) heat
- (H) tar
(answer). Air pollution harms the respiratory and circulatory systems. An example of an air pollution reaction is the production of photochemical smog. Smog harms the respiratory and circulatory systems.
The answer is (C)


(question). What has a range of sexual reproductive systems? 
Options:
- (A) Computer systems.
- (B) Most plants
- (C) animals
- (D) Roundworms.
- (E) mammals
- (F) Art reproductions.
- (G) insects
- (H) Stuffed toy bears.
(answer). Roundworms make up the phylum Nematoda. Within the Nematoda, a range of reproductive systems occur. A range of reproductive systems occur in roundworms.
The answer is (D)


(question). Energy that comes from body heat can help with 
Options:
- (A) recovery
- (B) commuting
- (C) movement
- (D) cooling
- (E) strength
- (F) stay warm
- (G) health
- (H) motion
(answer).

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Evaporation of sweat uses energy, and the energy comes from body heat. When sweat is evaporated into the air, it provides additional cooling. Cooling uses energy, and the energy comes from body heat.
The answer is (D)