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]: 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
[EX A]: C

[EX Q]: On a field trip, a student holds a frog and reports that it has slippery skin. This is an example of  
 (A) a measurement (B) a prediction (C) an explanation (D) an observation
[EX A]: D

[EX Q]: When soil becomes saturated during rainfall, excess water begins to collect on the surface. Downslope movement of this excess water to rivers, lakes, and streams is called  
 (A) runoff. (B) filtration. (C) groundwater. (D) condensation.
[EX A]:
A