Explanation:
Determining a substance's physical or chemical identity. What are the two main requirements for identification? The adoption of testing procedures that give characteristic results for specific standard materials and the number and type of tests needed to identify a substance to exclude all other substances.
Answer:
A cell is basically made of biological molecules (proteins, lipids, carbohydrates and nucleic acids). These biomolecules are all made from Carbon, hydrogen and oxygen. Proteins and nucleic acids have Nitrogen.
Explanation:
Ecosystem and pond,
not sure though but good luck !
