A compound is a molecule made of atoms from different elements. All compounds are molecules, but not all molecules are compounds. Hydrogen gas (H2) is a molecule, but not a compound because it is made of only one element. ... Atoms that share electrons in a chemical bond have covalent bonds.
Answer:
Protein
Explanation:
This is because protein is a macronutrients and it is the building blocks which is important for building body mass and they are found through out the body, in the muscles, bones, skin, hair e.t.c
Protein can be gotten from both plants and animals.
The animal protein include meat, diary products, fishes e.t.c.
The plants protein include beans, r.t.c.
all of the above can be considered ecosystems
