An element's atomic number is the amount of protons (positively charge subatomic particle found in the atoms nucleus) present in one atom of that element.
Mitochondria- it produces the energy for the cell. the muscle needs more energy because they are always functioning
Biological Organisms: Living things that are capable of reacting to stimuli, reproduction, growth, and homeostasis. Organisms are classified by taxonomy into specified groups such as the multicellular animals, plants, and fungi; or unicellular microorganisms such as a protists, bacteria, and archaea.
The answer would be respiratory because that system is used to breath oxygen and exhale carbon
