Describe the process of the light-independent stage of photosynthesis and the effect on it of decreasing light intensity.

The first stage of the light-independent stage, also referred to as the Calvin Cycle, is the fixation of CO₂ by RuBisCo which catalyses the reaction between CO₂ and ribulose bisphosphate (RuBP) to make an unstable six carbon intermediate. This breaks down to form 2 molecules of glyceraldehyde 3-phosphate (GP) which is reduced to triose phosphate (TP) using ATP and NADPH generated in the light-dependent stage of photosynthesis. Triose phosphate is then used to make a range of biological molecules, such as carbohydrates, nucleic acids, and lipids, and to regenerate ribulose bisphosphate.
A decreased light intensity will result in less ATP and NADPH being generated in the aforementioned light-dependent stage of photosynthesis. This will mean that GP is converted to TP at a slower rate, leading to the concentration of GP increasing and the concentration of TP decreasing. The decreased concentration of TP will mean there is less substrate available to regenerate RuBP, meaning that the concentration of RuBP will also decrease.