Answer:
The first living things on Earth, single-celled micro-organisms or microbes lacking a cell nucleus or cell membrane known as prokaryotes, seem to have first appeared on Earth almost four billion years ago, just a few hundred million years after the formation of the Earth itself.
They all form in great clouds of gas and dust, they begin life with same chemical composition as the Sun: about 3/4 hydrogen and 1/4 helium and no more than 2% consisting of elements heavier than helium. They DIFFER in size, age brightness, and temperature.
During glycolisys in cytoplasm, first step involves adding two phosphates to glucose molecule. This step requires the use of two ATP molecules. The next step is splitting 6 carbons glucose into two 3 carbons pyruvates. This step produces 4 ATPs and 2 NADHs. However, since we used up two ATPs during the initial phosphorylation, the net gain is only 2 ATPs
