TASK DEFINITION: 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.
PROBLEM: Which would be a safe practice to exercise during laboratory investigations?  
 (A) using open flames to heat all materials (B) keeping your cell phone on the laboratory countertop (C) knowing where your instructor/laboratory leader is at all times (D) removing your safety glasses when moving from station to station

SOLUTION: C

PROBLEM: An enclosed 20 mL metal cylinder was filled with a gas sample at room temperature. The sample then was transferred to an empty 40 mL enclosed container, also at room temperature. After being transferred, the volume of the gas was  
 (A) 10 mL. (B) 20 mL. (C) 30 mL. (D) 40 mL.

SOLUTION: D

PROBLEM: Research has shown that specialization of stem cells into specific cell types results, in part, from cell shape. What provides a specialized cell with its shape?  
 (A) number of mitochondria (B) presence of a nucleus (C) structure of the cytoskeleton (D) salt concentration of cytoplasm

SOLUTION:
C