You are given a science question (easy-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.

[Q]: What is the function of skin on the human body?  
 (A) Skin has pores that help the body sense odor. (B) Skin protects the body from harmful substances. (C) Skin brings oxygen directly into the body's bloodstream.
[A]: B


[Q]: The North America Nebula is named for its similarity in shape to the North American continent. It was discovered within the Milky Way by astronomer William Herschel in 1790. What was Mr. Herschel most likely observing?  
 (A) the explosion following the collapse of a star (B) a dense cluster of stars of varying magnitudes (C) meteorites as Earth passed through the tail of a comet (D) a cloud of hydrogen gas and dust where stars are born
[A]: D


[Q]: A condition in bees called "colony collapse disorder" occurs when worker bees leave the hive to collect nectar and never return. How would a decline in the bee population most likely affect a farm ecosystem?  
 (A) There would be a decrease in soil thickness. (B) There would be a decline in fruit production. (C) There would be an increase in plant diseases. (D) There would be an increase in insect pest populations.
[A]:
B