It's very likely you've covered photosynthesis before, and it's also very likely you'll cover it again. It's a biogeochemical cycle, meaning it is a pathway by which a chemical substance moves throughout biotic and abiotic parts of the earth.
It is important to remember the equation for photosynthesis, both for Biology and Geography. A reminder of it in both word and symbol form is below.
Word Equation for Photosynthesis
carbon dioxide + water → glucose + oxygen
Symbol Equation for Photosynthesis
[katex] CO_2 + 6H_2O \overset{\tiny\text{sunlight}} \longrightarrow C_6 H_{12} O_6 + 6O_2 [/katex]