Question

If the amount of carbon dioxide available to the plant approaches zero, what will happen to the plant's rate of photosynthesis?

Answer 1

The rate of photosynthesis will decrease as the amount of `CO_2` decreases.

Explanation:

Plants need three things to carry out photosynthesis: water, carbon dioxide and light.

`6CO_2 + 6H_2O + light -> C_6H_12O_6 + 6O_2`

It's like making sandwiches. The carbon dioxide is like bread, the water is like lunch meat and the products of photosynthesis (glucose, oxygen) are like a sandwich. It doesn't matter if you have loads of lunch meat - if you don't have any bread, you can't make any sandwiches!

Here is a video which discusses an experiment which tests the impact of varying carbon dioxide levels on the rate of photosynthesis.

Hope this helps!