What is the energy source plants use to produce high energy sugars?

1 Answer

The sun (light energy).

Explanation:

This process is called photosynthesis and the production of sugar is specifically in the light independent part of photosynthesis called the Calvin cycle.

In the Calvin cycle, #CO_2# is converted to sugar using the enzyme RuBisCo, ATP, and NADPH. The ATP and NADPH are products from the light dependent part of photosynthesis.

Here's a diagram of the Calvin cycle:

https://en.wikipedia.org/wiki/Light-independent_reactions