Which of the following statements regarding matter is false?
all matter has mass.
all life is composed of matter.
all matter exists in the form of compounds.
all matter is composed of elements.

All matter exists in the form of compounds.

Explanation:

Matter is anything that has weight and occupies space. For anything to have weight, it must have mass. Weight is a product of mass and gravity.

The atom is the simplest form of matter. When atoms combines as elements, they form molecules and compounds.

Matter can exist as atom, element, compounds and mixtures.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.