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: Which statement best describes the development of a human embryo?  
 (A) A single cell becomes many cells. (B) Each cell has a different function. (C) Many cells combine to form one cell. (D) All the cells have the same function.

SOLUTION: A

PROBLEM: Which would provide evidence of seafloor spreading?  
 (A) higher levels of salinity in the ocean water (B) stronger currents at the surface of the ocean (C) cooled magma found on the edge of the plates (D) greater reproduction levels for organisms at the bottom of the ocean

SOLUTION: C

PROBLEM: Which region of the Milky Way contains a population that consists mostly of old stars?  
 (A) the halo (B) the spiral arms (C) the nuclear bulge (D) the open clusters

SOLUTION:
A