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 a main feature of plains?  
 (A) a flat, level surface (B) a high, steep peak (C) a low, shallow basin (D) a gentle, gradual slope
[A]: A


[Q]: A student walking quickly while carrying an orange on his lunch tray stops suddenly. The orange will most likely roll off the tray due to  
 (A) inertia of the orange. (B) centripetal force of the orange. (C) the friction acting on the orange. (D) the balanced forces acting on the orange.
[A]: A


[Q]: Which of the following is an example of a behavioral adaptation?  
 (A) hooves of a horse (B) migration of birds (C) a spider web (D) a bee hive
[A]:
B