Question

which evidence is most likely used to indicate the beginning of solar system formation?
materials combined to form a mass.
materials were pulled together by gravity.
water condensed and collected to form oceans.
different species of microorganisms lived on earth.

Explanation:

The solar system formation is believed to have started with the gravitational pull on materials. The nebular hypothesis states that the solar system formed from a rotating cloud of gas and dust (the solar nebula) which collapsed under its own gravity. The other options are not related to the start of solar system formation. "Materials combined to form a mass" is too vague without the gravitational aspect. "Water condensed and collected to form oceans" is related to Earth's development after the solar system was already forming. "Different species of microorganisms lived on Earth" is related to Earth's biological history, long after the solar system's formation began.

Answer:

Materials were pulled together by gravity.