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.

Input: Consider Input: A population of plants growing on an island consisted of two varieties, one with thorns and the other without. Over a period of many years, the variety with thorns gradually disappeared. Which process most likely brought about this change in the plant population?  
 (A) gene flow (B) genetic drift (C) natural selection (D) random mutation

Output: C


Input: Consider Input: India is in the Northern Hemisphere and Australia is in the Southern Hemisphere. In June, it is summer in India and winter in Australia. What is the main reason the seasons are opposite in the two countries?  
 (A) because Earth is tilted on its axis (B) because the Sun rotates on its axis (C) because Earth revolves around the Sun (D) because of the distance between the countries

Output: A


Input: Consider Input: According to the endosymbiotic theory, double-membrane mitochondria originated as a result of some larger eukaryotic cells with flexible membranes engulfing smaller prokaryotic cells. Which of these explains where the outer layer of the double membrane of the mitochondria originated?  
 (A) the plasma membrane of the eukaryotic host (B) the nuclear membrane of the eukaryotic host (C) the ribosomes of the engulfed prokaryotic cell (D) the lysosomes of the engulfed prokaryotic cell


Output: A