Question

**Fill in the blanks**

According to one theory, Earth’s moon accreted to form its current structure following a giant impact between Earth and another celestial body. Complete the paragraph to describe the process of accretion.

Following the impact, a section of Earth broke off. As a result, large pieces of debris started to revolve around Earth. The debris was held close to Earth by Earth’s ___. The debris frequently collided to form a planetesimal. As the planetesimal grew in size, its gravity increased. This gravitational force pulled in even more ___ , which led to the accretion of the moon.

**First Blank Options**
1) Atmosphere
2) Rotational Motion
3) Gravity
4) Oceans

**Second Blank Options**
1) Matter
2) Gravity
3) Atmosphere
4) Theories

Answer 1

1. Gravity

2. Matter

Step-by-step explanation:

According to Giant impact theory, when a Mars sized object collide with the Earth, the debris was held close to Earth due to its gravity. The debris collided frequently forming a planetesimal which grew in size overtime. Thereby, the gravity increased and pulled even more matter. The accretion of this matter eventually formed the Moon.

Answer 2

Word for the first blank: gravity

Word for the second blank: matter

Step-by-step explanation:

The only way debris from the impact with Earth can be held close to Earth is due to a force. The only force that could be acting from Earth is "the force of gravity".

The gravitational pull of this new object being formed, increases proportional to its mass as more and more "matter" accumulates. And the accretion process is now on its way.