Energy that is not passed on from one trophic level to the next is

a.
lost as heat
b.
returned to the sun
c.
destroyed
d.
all of the above

The correct answer for the blank is a.  lost as heat.

Trophic level corresponds to a particular rank of an organism in a food chain within an ecosystem ( such as producers and primary consumers occupy the first trophic and the second trophic level respectively).

According to the 10 percent rule of energy transfer, only 10% of the energy ( in the form of organic matter) is transferred from one (lower) trophic level to the next (higher) trophic level and the remaining is utilized in the cellular processes and lost as heat in the surrounding.

Thus, option A) is the right answer.

a. the production of carbon dioxide through the process of photosynthesis

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."