When the solar system was forming, the building blocks from which the protoplanets gathered together were the:
A) gold, iron, and nickel atoms
B) planetesimals (a few km to tens of km wide)
C) giant accretion grains about the size of Mars
D) extremely hot clouds of gas torn out of the Sun, which was already shining brilliantly
E) pure water ice crystals, about the size of a snowflake

Question

Quizplus · Accepted Answer

Planetesimals, which range from a few km to tens of km in size, were the building blocks from which protoplanets gathered during the formation of the solar system. The other options are not accurate descriptions of these building blocks.

When the Solar System Was Forming, the Building Blocks from Which