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:

According to the nebular hypothesis, the solar system began to form when a large cloud of gas and dust (the solar nebula) started to collapse due to gravity. As the materials were pulled together by gravity, the density and temperature at the center increased, eventually forming the Sun, and the remaining materials formed the planets and other objects in the solar system. The other options are not related to the beginning of solar system formation. Water condensing to form oceans (if it were on a planet) and microorganisms living on Earth are events that occur much later in the history of a planet (like Earth), long after the solar system has already formed. Just materials combining to form a mass is too vague compared to the gravitational pull which is a key mechanism in the formation of the solar system as per scientific theories.

Answer:

Materials were pulled together by gravity.