Answer: carbon dioxide gas is the reactant in the chemical reactions of photosynthesis.
Explanation:
When plants make their own food with the help of sunlight, carbon dioxide and water then the process is known as photosynthesis.
Therefore, carbon dioxide gas is the reactant in the chemical reactions of photosynthesis.
The equation for photosynthesis reaction is as follows.
[tex]6CO_{2}+6H_{2}O+lightenergy \overset{photosynthesis}{\rightarrow}C_{6}H_{12}O_{6} + 6O_{2}[/tex]
