When two or more substance are combined and cannot be separated?

Answer 1

matters, according to the law of gravity. everything is connected in someway by gravitational field, no matter how they combined or separated, they are still connected in someway.

Answer 2

When two or more substances are combined and cannot be separated by physical means, they form a mixture. This could be a homogeneous mixture, where the substances are evenly distributed like salt in water, or a heterogeneous mixture, where the substances are unevenly distributed like oil and water. If the substances form a new substance with its own unique properties and characteristics, it is a chemical reaction.