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.

Which of the following is most likely to disrupt the natural balance in an ecosystem?  
 (A) introduction of a non-native species (B) reduced daylight hours during winter (C) preventing the cutting of trees in forests (D) riverbank erosion resulting from springtime flooding
A

The Great Ocean Conveyer ocean current system runs north through the Atlantic from the equatorial region. If this current got disrupted, North American and European climates would become  
 (A) rainier. (B) colder. (C) windier. (D) more humid.
B

Which feature is most likely the result of a flowing river?  
 (A) a sand dune (B) a volcano (C) a canyon (D) a glacier

C