Alternative energy sources do not use fossil fuels is the answer

Correct do not use fossil fuels is the answer

3-PGA is the important metabolic intermediate in light independent reactions of photosynthesis.

PGA

Explanation:

Light-independent reaction in photosynthesis is called Calvin cycle and the reaction doesn’t directly require sunlight. But it still needs the products of light reaction. In light-independent reaction carbon dioxide is fixed from inorganic  form into an organic form.

In the fixation each molecule of carbon dioxide reacts with RuBP and forms two molecules of 3-PGA at a time. The reaction is catalyzed by the enzyme RuBisCO. Since 3 molecules of RuBP are involved a total of 6 molecules of 3-PGA will be formed in fixation.

Here the 3-PGA is the intermediate and in the next stage it will get reduced to G3P(Glyceraldehyde -3 phosphate).