For glycolysis to produce atp when no oxygen is present, it is necessary for cells to convert to
a. atp to nad+
b. atp to adp
c. nadh to atp
d. nadh to nad+

The answer is D. NADH to NAD+

When no oxygen is present, anaerobic respiration occurs.It is the only way to produce ATP in this condition.NAD+ is necessary because it is converted into NADH and at the same time ADP is converted to ATP in the reaction of pyruvate synthesis from glucose.Therefore, NADH must be converted to NAD+ in order to have NAD+ always present in the cell.

C) reflection (i also looked up the other choices just to make sure)

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.