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.

[EX Q]: Diseases that can be transmitted between organisms are
(A) infectious. (B) inherited. (C) environmental. (D) congenital.
[EX A]: A

[EX Q]: A bird eats a brightly-colored insect that tastes bad. The bird avoids preying on this type of insect again. This example is best described as
(A) a physical characteristic. (B) a learned behavior. (C) an inherited behavior. (D) an adaptation.
[EX A]: B

[EX Q]: People can help keep a forest a good place for birds to live by
(A) dumping garbage in a small part of the forest (B) building a road through the middle of the forest (C) burning dead trees to make smoke in the air (D) preventing too many trees from being cut down
[EX A]:
D