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: While Anna was testing a circuit, she dropped a light bulb. What is the safest thing Anna can do?  
 (A) get a new bulb to finish the test (B) push the broken glass under a table (C) tell her teacher that she broke the bulb (D) ask her partner to help pick up the broken glass

SOLUTION: C

PROBLEM: 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

SOLUTION: C

PROBLEM: Conjugation in a paramecium differs from sexual reproduction in volvox because conjugation  
 (A) results in two genetically identical cells. (B) requires specialized gonidia cells. (C) forms haploid male and female gametes. (D) takes place between specialized cells.

SOLUTION:
A