This is the force of attraction between an object and the earth due to gravity.

Gravitational force

Explanation:

Gravitational force is the force that attracts an object down to the earth. It’s also the reason why we don’t float on this planet. This force is also why anything that isn’t thrown up must come down.

In space and other planets with little or no gravitational force ,organisms float over there which makes its inhabitation by organisms very difficult.

complete the square on the right side of the equation;

-5(x + 0)^2 + 15

answer: d. y = -x^2 + 15

a physical change is being made.