What can you infer about the amount of sunlight around the equator that could explain why these areas tend to have higher concentrations of chlorophyll?

The sun is located directly ocver the equator therefore the most amount of sunlight would be present in this area . The plants here would use this as a way to photosyntesise more by having more chlorophyll present in leaves . The CO2 conc. , water conc. would be other factors but the amount of chlorophyll would be a direct limitation as there can always be excess CO2 and Water