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: What are produced in both the male and female reproductive systems in humans?  
 (A) sperm (B) nutrients (C) fertilized eggs (D) sex cells

SOLUTION: D

PROBLEM: Which is the best evidence for the theory of continental drift?  
 (A) the appearance of volcanoes at the boundaries where plates collide (B) earthquakes at boundaries where one plate slides past another (C) cases where a species exists in only one isolated place (D) fossils of the same species found on widely separated continents

SOLUTION: D

PROBLEM: Which conclusion can be made about earthworms because they do not have an internal skeleton?  
 (A) They are invertebrates. (B) They have radial symmetry. (C) They are made of one segment. (D) They have an open circulatory system.

SOLUTION:
A