A group of atoms bonded together
A water molecule consists of two atoms of hydrogen linked by covalent bonds to the same atom of oxygen. Atoms of oxygen are electronegative and attract the shared electrons in their covalent bonds.
Wolves are causing a trophic cascade of ecological change, including helping to increase beaver populations and bring back aspen, and vegetation.beavers.
I might be incorrect, but from what I remember it should be particle size
