Question

does burning fossil fuels enhance or decrease photosynthesis?
○ neither: burning fossil fuels releases co₂, which is taken up by living photosynthetic organisms, making the process \carbon neutral.\
○ enhance: burning fossil fuels provides the co₂ necessary to grow cyanobacteria in municipal wastewater and bioreactors.
○ enhance: burning fossil fuels releases co₂, which is a substrate for photosynthesis.
○ decrease: burning fossil fuels releases pollution, which has a negative effect on photosynthesis.
○ decrease: burning fossil fuels releases greenhouse gases that increase earth’s temperature, thus inhibiting photosynthesis.

Explanation:

Photosynthesis uses CO₂ as a key substrate (along with water and light energy) to produce glucose and oxygen. Burning fossil fuels increases atmospheric CO₂ levels, which can act as a limiting factor for photosynthesis—higher available CO₂ typically enhances the rate of photosynthesis in many plants and photosynthetic organisms. Other options are incorrect: the process is not carbon neutral (fossil fuel CO₂ is ancient and adds to the carbon cycle), the cyanobacteria example is too specific and not the general effect, and while pollution/temperature effects exist, the direct substrate role of CO₂ is the primary general impact addressed here.

Answer:

Enhance: Burning fossil fuels releases CO₂, which is a substrate for photosynthesis.