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 the function of the nucleus in a cell?  
 (A) provides energy (B) provides nutrients (C) controls activity (D) controls movement
[A]: C


[Q]: When oxygen combines with hydrogen, which substance is formed?  
 (A) water (B) vinegar (C) hydrochloric acid (D) hydrogen dioxide
[A]: A


[Q]: The discovery of tectonic plates and the cause of their movement is best described as a result of which scientific procedure?  
 (A) direct observation of the important properties of the Earth system (B) controlled laboratory experimentation on a simulation of geological systems (C) methodical testing of a valid hypothesis statement (D) inquiry into the causes of observed geological phenomena
[A]:
D