13. during photosynthesis, carbon dioxide and water combine according to the general
equation:
energy
carbon dioxide + water sugar + oxygen
why is photosynthesis a chemical reaction?
a because new substances are formed
b. because an input of energy is required
c. because the reactants are compounds
d. because the products include an element
cray, metallic zinc filings were added to a heaker of dilute hydrochloric acid in a fume hond.

The picture represents the process that produces most of the energy used by living organisms on earth. which process is represented in the picture? a) the magnetic attraction between two hydrogen nuclei. b) the fusion of hydrogen nuclei to produce a helium nucleus in the core of the sun. c) the fission of hydrogen nuclei to produce a helium nucleus in the core of the sun. d) the chemical reaction between hydrogen nuclei to produce a helium nucleus in earth's atmosphere.