Answer
Glucose contains lots of energy, which can be obtained from the abundant energy in sunlight by the light reactions. To derive this complex molecule with such a high potential energy, many energy-rich NADPH and ATP molecules must be used up during the Calvin cycle.
Work Step by Step
This question is asking you to see the large amount of energy on two sides of an equation, 1) The reactant side of the net equation for the Calvin cycle which uses ATP and NADPH and 2) The product side where glucose appears.