<span>Answer:
There are only two real sources of energy on the earth. One comes from geothermal from the creation of the earth and the other comes from the sun. You can say wind and nuclear or water, but water's movement is related to the tectonic activity and shaping of the earth and its spin, wind comes from unequal heating of the earth by the sun and nuclear energy comes from isotopes that were formed by a star. So producers are able to harness one of those two energy sources, the sun. Trees and plants are so common because they are using free energy, they have discovered a way to get something for nothing essentially. Predators can use the nutrients they make to supply their own energy but in the end everything boils down to the producers ability to make energy from the sun.</span>
Covalent bonding occurs when pairs of electrons are shared by atoms. Atoms will covalently bond with other atoms in order to gain more stability, which is gained by forming a full electron shell. By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability
Answer:
Atmospheric carbon dioxide (from animals)
Explanation:
The carbon atoms in glucose come from the atmospheric carbon dioxide molecules that are taken in by plants for photosynthesis.
Hope this helps!