Which of the following statements about asteroids is true?
a. asteroids are all very large and are mostly made up of stone, iron and nickel.
b. asteroids are all very large and are mostly made up of frozen water and gas.
c. asteroids vary greatly in size and are mostly made up of frozen water and gas.
d. asteroids vary greatly in size and are mostly made up of stone, iron and nickel.

Stone, Iron, and Nickle

Explanation: Study island ;)

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.