What are the two elements sand is made of? *

tiny crystals of the mineral quartz, which is made out of silica and oxygen

Well, much of the world's sand is made out of the same stuff, tiny crystals of the mineral quartz, which is made out of silica and oxygen, the two most common elements in Earth's crust.

answer: cellular respiration takes in food and uses it to create atp, a chemical which the cell uses for energy. usually, this process uses oxygen, and is called aerobic respiration. it has four stages known as glycolysis, link reaction, the krebs cycle, and the electron transport chain.