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]: Which illustrates the correct order of relationships in organisms?  
 (A) tissue -> organ system -> organ -> cell (B) organ -> cell -> organ system -> tissue (C) cell -> tissue -> organ -> organ system (D) organ system -> organ -> cell -> tissue
[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]: Two tectonic plates pushing toward each other cause intense heat and pressure in Earth's crust. Into which will crust material be changed by heat and pressure?  
 (A) fossils (B) sediments (C) igneous rock (D) metamorphic rock
[A]:
D