question... Many corals secrete what to form a coral reef?
Options:
- (A) Chlorophyll
- (B) salt and water.
- (C) The area was once underwater
- (D) Chemical energy
- (E) aqueous solution
- (F) Organic compounds
- (G) gastropod shells
- (H) hard outer covering
answer... Many corals secrete an exoskeleton that builds up to become a coral reef. An insect has a hard outer covering called an exoskeleton. Many corals secrete a hard outer covering that builds up to become a coral reef.
The answer is (H)

question... Humans have collected and grown what for food for thousands of years?
Options:
- (A) plants
- (B) fungi
- (C) ferns
- (D) cheese
- (E) fungus
- (F) salmon
- (G) hamburgers
- (H) primates
answer... Humans have collected and grown mushrooms for food for thousands of years. Mushrooms are an example of fungi. Humans have collected and grown fungi for food for thousands of years.
The answer is (B)

question... What do sense organs help bullfrogs do?
Options:
- (A) excrete waste
- (B) empty gall bladder
- (C) An object is seen
- (D) Move to another area
- (E) Catch prey
- (F) protect them
- (G) smell and eat
- (H) smell and taste
answer...
Amphibians have sense organs to smell and taste chemicals. Bullfrogs eat other amphibians. Bullfrogs can smell and taste chemicals through sense organs.
The answer is (H)