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.

What season is the Northern Hemisphere experiencing when it is tilted away from the Sun?  
 (A) spring (B) summer (C) autumn (D) winter
D

Why should plants be included in investigations about the water cycle?  
 (A) Plants speed up the water cycle by removing carbon from the air. (B) Plants start the water cycle when they make water in photosynthesis. (C) Plants are part of the water cycle through the process of transpiration. (D) Plants stop the water cycle because they absorb it and stop the flow to streams.
C

The force of gravitational attraction between Earth and any object on Earth is measured as  
 (A) mass. (B) weight. (C) volume. (D) density.

B