Q: What happens when people flow into or out of a population?
Options:
- (A) genetic morphing
- (B) death
- (C) gene flow
- (D) movement
- (E) generic flow
- (F) interact
- (G) competition
- (H) gene expression
A: So, my chain of thought: Gene flow occurs when individuals move into or out of a population. People are individuals, and each person has different needs. Gene flow occurs when people move into or out of a population. The answer is (C).

Q: What has woody stems covered with bark?
Options:
- (A) sunflowers
- (B) Newton
- (C) ferns
- (D) seaweed
- (E) Most plants
- (F) palm trees
- (G) evergreens
- (H) orchids
A: So, my chain of thought: Trees have woody stems covered with bark. Orange trees are evergreen trees. Evergreens have woody stems covered with bark. The answer is (G).

Q: What is a chemical element essential for good health?
Options:
- (A) sweating
- (B) light energy
- (C) oxygen
- (D) bioaerosols
- (E) Chlorophyll
- (F) hydration
- (G) Potassium
- (H) fever
A:
So, my chain of thought: Minerals are chemical elements that are essential for body processes. Potassium is a trace mineral essential for growth and good health. Potassium is a chemical element essential for good health. The answer is (G).