1. The idea that geologic processes that occur today are similar to
those that have occurred on Earth in the past.

uniformitarianism

Explanation:

Uniformitarianism, in geology, is the doctrine suggesting that Earth's geologic processes acted in the same manner and with essentially the same intensity in the past as they do in the present and that such uniformity is sufficient to account for all geologic change.

explanation:

the universal gravitation equation. since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. if the mass of one of the objects is doubled, then the force of gravity between them is doubled.