[Q] What have a centralized nervous system with a brain?
Options:
- (A) objects that have mass
- (B) warm-blooded
- (C) Earth orbiting the Sun
- (D) jellyfish
- (E) salmon only
- (F) bass only
- (G) bass and salmon
- (H) chickens
[A] Here's my solution: Fish have a centralized nervous system with a brain. Fish include bass and salmon. Bass and salmon have a centralized nervous system with a brain. The answer is (G).

[Q] Cancer and tumors are a result of specific types of:
Options:
- (A) organs
- (B) cigarettes
- (C) radiation
- (D) layers of fat
- (E) gene damage
- (F) rays or beams
- (G) Chemical energy
- (H) the skin
[A] Here's my solution: Cancer is a disease in which cells divide out of control. With specific types of gene damage, the cell starts dividing out of control, forming a tumor. Cancer and tumors are a result of specific types of gene damage. The answer is (E).

[Q] A response to what occurs when many muscles contract a little at once?
Options:
- (A) heat
- (B) cold
- (C) sweat
- (D) pain
- (E) forces
- (F) stress
- (G) comfort
- (H) motion
[A] Here's my solution: Shivering occurs when many muscles contract a little bit all at once. Another response to cold is shivering. A response to cold occurs when many muscles contract a little at once. The answer is (B).

[Q] How do echinoderms use their feet to locomote themselves?
Options:
- (A) one at a time
- (B) to move people
- (C) running and lifting
- (D) protein channels
- (E) a hydraulic system
- (F) it needs them
- (G) undulations
- (H) It helps them survive
[A]
Here's my solution: Echinoderms have a unique water vascular system with tube feet. Echinoderms have a hydraulic system of locomotion called the water vascular system. Echinoderms have a hydraulic system of locomotion with tube feet. The answer is (E).