Two masses exerting force on each other is an example of what

Whenever two objects are touching, they usually exert forces on each other. The force of gravity, on the other hand, is an example of a force that exists between objects without them having to be in contact. Objects with mass exert forces on each other via the force of gravity.

PLEASE GIVE BRAINLIEST

Type in the minus sign

It's either -limiting factors or -scarce resources but i'd go with my first answer since the food and water are abundant they really aren't scarce