Q: What is one thing most single-celled organisms have in common?
Options:
- (A) Energy
- (B) glucose
- (C) bacteria
- (D) motility
- (E) Energy.
- (F) heat energy
- (G) resistance
- (H) warmth
A: So, my chain of thought: Most protists have motility. Protists Protists are single-celled organisms. Most single-celled organisms are motile. The answer is (D).

Q: What falls decreasingly on the earth from the equator to the poles?
Options:
- (A) autumn
- (B) heat
- (C) chill
- (D) Vapor
- (E) Energy
- (F) cold
- (G) summer
- (H) Mass
A: So, my chain of thought: Temperature falls from the equator to the poles. Temperature is a measure of the amount of heat. Heat falls from the equator to the poles. The answer is (B).

Q: Phylum platyhelminthes are mostly what?
Options:
- (A) animals
- (B) engorged
- (C) fungi
- (D) infected
- (E) parasitic
- (F) insects
- (G) huge
- (H) free living
A:
So, my chain of thought: Flatworms belong to the phylum Platyhelminthes. Most of the flatworms are parasitic, although the Turbellaria are free-living in fresh water. Phylum Platyhelminthes are mostly parasitic. The answer is (E).