[Q] What can be caused by direct or passive inhalation?
Options:
- (A) skin grafts
- (B) prolonged thirst
- (C) science
- (D) Toxicity
- (E) lung cancer
- (F) negative
- (G) friction
- (H) craters
[A] Here's my solution: Lung cancer is most often caused by exposure to tobacco smoke. Smoke Tobacco smoke , whether directly or passively inhaled, has been shown to worsen asthma. Lung cancer can be caused by direct or passive inhalation. The answer is (E).

[Q] What is part of an animal's excretory system?
Options:
- (A) alveoli
- (B) garbage chute
- (C) pollen
- (D) glucose
- (E) bloodstream
- (F) kidneys
- (G) food
- (H) intake
[A] Here's my solution: Organs of excretion make up the excretory system. Leptospiral organisms cause infection in the kidneys and are excreted in urine. Kidneys are part of the excretory system. The answer is (F).

[Q] Why can amphibians easily absorb toxins?
Options:
- (A) salamanders
- (B) permeable skin
- (C) hydrate their cells
- (D) it needs them
- (E) poisonous frogs
- (F) Pesticides
- (G) cold blooded
- (H) bending light rays
[A] Here's my solution: Amphibians have permeable skin that easily absorbs substances from the environment. Natural Toxins Toxins are poisonous substances from bacterias, plants or animals. Amphibians have permeable skin that can easily absorb toxins from bacterias, plants or animals. The answer is (B).

[Q] Introns are areas that
Options:
- (A) it keeps an organism warm
- (B) Plant reproduction
- (C) the wearing away of rock
- (D) do not code for protein
- (E) Something coming from a gland
- (F) Plant growth is reduced
- (G) allow growth
- (H) produce offspring
[A]
Here's my solution: Introns are regions that do not code for proteins. An area is a rectangular region of cells. Introns are areas that do not code for proteins. The answer is (D).