Answer: It is a fruit
Explanation:
More specifically it is neither root nor stem.
Wait, you have to sketch this stuff? Then YOU need to sketch it. No offence, just no one is gonna sketch this for you.
If CO2 was in very small amounts then it would be the limiting factor of photosynthesis, this means the process will take place at a much slower rate because it is lacking one of the raw materials it needs for the process to occur. To find the optimum light intensity you really need all other factors to be at optimum levels or in abundance.
Sunlight Water and good soil
