Answer: Thru Photosynthesis
Explanation: This is the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.
Asteroids vary greatly in size and are mostly made up of frozen water and gas. This one is true.
They are said to be "mostly formed of ice and gas" as they rarely can be found consisting of stone, nickel and iron. These are extremely dangerous in our Universe.
They made the cell theory, concluding that all living things are made of cells.
