Q: Streams may start with runoff seeping out of water containing what?
Options:
- (A) chemicals
- (B) Nutrients
- (C) Nitrous oxide
- (D) Helium
- (E) Lithium
- (F) Sulfur
- (G) soil
- (H) Sediment
A: So, my chain of thought: Streams may start with runoff or water seeping out of a spring. Sulfur occurs native in the vicinity of volcanoes and hot springs. Streams may start with runoff or water seeping out of a body of water where sulfur occurs. The answer is (F).

Q: Where do corals form large colonies?
Options:
- (A) Mars
- (B) new World
- (C) Sediment
- (D) shoreline
- (E) environment
- (F) Absorb light
- (G) loose soil
- (H) polyps
A: So, my chain of thought: Corals form large colonies in shallow tropical water. Water is shallow at the shore with gradual deepening. Corals form large colonies at the shoreline. The answer is (D).

Q: Amphibians have what sort of sensing system?
Options:
- (A) strong
- (B) retina
- (C) four limbs
- (D) chemical
- (E) mechanical
- (F) the eyes
- (G) nerves
- (H) heat or cold
A:
So, my chain of thought: Amphibians have sense organs to smell and taste chemicals. Smell and taste belong to our chemical sensing system. Amphibians have a chemical sensing system. The answer is (D).