You are given a science question (hard-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]: Elephants on the African savanna eat shrubs and small trees. This behavior clears land and enables grass to grow. Grazers such as gazelles eat the grass. Lions prey on the gazelles. Which two organisms in this scenario are in the most cooperative relationship?   
 (A) the elephants and the shrubs (B) the shrubs and the lions (C) the elephants and the gazelles (D) the gazelles and the lions
[EX A]: C

[EX Q]: An infectious disease causes an increase in the body temperature and a decrease in the blood glucose levels of a deer. What is most likely an effect of this disease?  
 (A) a disruption in the homeostasis of the deer (B) a change in the genetic makeup of the deer (C) an increase in the energy level of the deer (D) an increase in the reproductive rate of the deer
[EX A]: A

[EX Q]: Which factor best explains how many diseases, such as cancer, are formed within the body?  
 (A) A traumatic injury to the body has occurred. (B) A disruption in the cell cycle has taken place. (C) A response by the immune system was triggered by an allergic reaction. (D) A mutation occurred during the process of crossing over.
[EX A]:
B