Accretion was one of the processes responsible for heating up earth’s core in the

A and C are your answers i think.

A.) Gravity increases as mass increases.

C.) Frequency of collisions increases as gravity increases.

Explanation:  

The heating of core of Earth was due to accretion process and some other factors.

Accretion is the process in which particles accumulate due to force of gravity and grow into a massive object. As the mass increase, so does the gravity. The frequency of collisions increases. Particles collide and stick with each other. This generates large amount of heat.

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Explanation:

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