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: A potential negative impact of building a dam on a river is that the dam   
 (A) prevents sediment from flowing downstream. (B) increases the amount of water available to farms. (C) prevents seasonal downstream flooding. (D) increases the rate of water loss from a lake.

Answer: A


Question: Which of these has the greatest capacity for storing thermal energy from the Sun?  
 (A) air (B) land (C) oceans (D) plants

Answer: C


Question: A group of students is investigating two substances to determine which is table salt and which is table sugar. How would the students best identify each substance?  
 (A) by noticing if they dissolve in water (B) by studying the color of the substance (C) by observing if they stick to a surface (D) by examining the shape of the crystal

Answer:
D