(question). What do nephrons filter?
Options:
- (A) Blood
- (B) matter
- (C) solutes
- (D) Energy
- (E) SO2
- (F) Gases
- (G) Energy.
- (H) cations
(answer). Nephrons are the structural and functional units of the kidneys. Blood is filtered in the kidney. Nephrons filter blood.
The answer is (A)

(question). The transfer of pollen to what is the fertilization step of the sexual reproduction of a plant?
Options:
- (A) stigma
- (B) apples
- (C) flowers
- (D) embryos
- (E) potatoes
- (F) seeds
- (G) eggs
- (H) plants
(answer). Pollination is the fertilization step in the sexual reproduction of plants. Pollination is the transfer of pollen grains to a stigma. The transfer of pollen grains to a stigma is the fertilization step in the sexual reproduction of plants.
The answer is (A)

(question). What can mutations cause?
Options:
- (A) death and devastation
- (B) blood
- (C) massive damage
- (D) Leptospirosis
- (E) biological diversity
- (F) horses
- (G) ice
- (H) out of control growth
(answer). Cancer cells divide more often than normal cells, and grow out of control. Cancer is an example of a mutation in cells. Mutation can cause growth out of control.
The answer is (H)

(question). What is one thing studied in immunology?
Options:
- (A) illness
- (B) antigens
- (C) humanism
- (D) health
- (E) philosophy
- (F) resistance
- (G) symbology
- (H) fever
(answer).
Antigens are molecules that the immune system recognizes as foreign to the body. Immunology is the study of the immune system. Immunology includes the study of antigens.
The answer is (B)