The nucleus of an atom contain protons and neutrons, which make up most of the mass of an atom.
The answer would be 2 and 3 ( 2nd answer choice)
It’s the source of all the energy from all the stars ... until their fuel is used up
Anaerobic respiration (without oxygen) would caused muscle cells to produce lactic acid. This causes the muscles to ache and in the long term, damages them. Also anaerobic respiration releases far less energy (ATP) than aerobic respiration. So it is best for muscle cells to respire aerobically as they need more energy.
Scientists<span> are people who use research and experiments to learn more about the natural world. </span>Scientists<span> use scientific methods to derive knowledge systematically, performing repeatable experiments to ensure that their conclusions are valid and accurate.</span>
