The time period being referred to is the sensitive period. This time period is also referred to as the critical period. The importance of a critical period is such that it must involve certain stimuli from which an organisms learns and acquires traits. If some of these stimuli are not present in the critical period, the organism has difficulty acquiring the trait or skill, and may even find it to be impossible to learn the skill.
Answer:
It will increase the rate of photosynthesis as there will be more carbon dioxide ... however there may be a limiting factor which will limit the rate to keep it constant... Such as the opening if the stomata to receive more CO2 which in turn causes loss of water by transpiration.