The chemical formula of oxygen is o2 that means it is a single compound or molecule gas? it is pure substance or mixture?

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder

In salt water solution,the salt is the blank

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a.the mitochondria b.the nucleus c.the vacuoles d.the endoplasmic reticulum