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]: A puppy has traits from its mother and its father. Which of these structures provides genetic information from the father to the puppy?  
 (A) a muscle cell (B) a nerve cell (C) a blood cell (D) a sperm cell
[EX A]: D

[EX Q]: The systems of the human body work together. Which system works with the skeletal system by pulling on the bones to create movement?  
 (A) digestive (B) circulatory (C) muscular (D) nervous
[EX A]: C

[EX Q]: The formation of the Grand Canyon has most likely taken how long?  
 (A) several years (B) hundreds of years (C) thousands of years (D) millions of years
[EX A]:
D