Organ system, because there are multiple organs that work together to help make the body function.
Answer: covalent bond is the force of attraction that holds together two atoms that share a pair of valence electrons. Covalent bonds form only between atoms of nonmetals. The two atoms that are held together in a covalent bond may be atoms of the same element or different elements.
Explanation:
<span>By studying fossils, scientists get an idea of what the organisms looked like, what they ate, and how they lived. </span>
