instruction:
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.
question:
Which example best shows structures that make up the digestive system in the human body?  
 (A) heart, blood, vessels (B) nose, trachea, lungs (C) brain, spinal cord, nerves (D) esophagus, stomach, intestines
answer:
D


question:
Laura adds 50 mL of boiling water to 100 mL of ice water. If the 150 mL of water is then put into a freezer, at what temperature will the water freeze?  
 (A) 0°C (B) 15°C (C) 37°C (D) 50°C
answer:
A


question:
A cell that is low in water will most likely immediately lose the ability to  
 (A) remain rigid. (B) absorb sunlight. (C) release oxygen. (D) reproduce again.
answer:

A