An adult , or mature i think sry if not the answer you were looking for
Answer:
The correct answer is 3 countering the affect of declining CO2 on photosynthesis.
Explanation:
Carbon di oxide is an important reactant of photosynthesis.The atmospheric CO2 label regulates the rate of photosynthesis.
When the label of atmospheric CO2 decrease the photosynthesis rate also declines.
So to countering the effect of declining CO2 on phosynthesis plants increase the number of stomata in their leaves.
That’s the only part I know (might not be right not to sure)