Answer:
Cell,tissue, organ, organ system, Organism
Explanation:
because cells make tissues and tissues make organs and many organs make organ systems.
Answer:
Oxygen and glucose are both reactants in the process of cellular respiration. The main product of cellular respiration is ATP; waste products include carbon dioxide and water.
Scientists believe that the Earth's early atmosphere lacked oxygen because photosynthetic organisms did not yet exist. Hope this helps and have a great day!
