Hummingbirds are an example of a because of the pollination they provide.

The correct answer is "pollinator".

Explanation:

Insects are the first animals that come to mind when we think about pollinators, however hummingbirds are an excellent example of pollinators as well. Hummingbirds feed frequently from flowers, transferring grains of pollens from a flower to others. Some species of flowers have adapted to develop some traits to attract hummingbirds, such as certain color, shape and scent.

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.

sex cells are usually half's then they find another half and make a fertilize egg