The answer to this question would be: smell
The sensory organ that catch smell is located in the nose and will send the signal into the olfactory bulb. The olfactory bulb is located in the bottom part of the brain, near the hippocampus(which was the center of memory), and amygdala (which was the center of emotion).
In order for energy to be able to be created, ATP(adenosine triphosphate) needs to form in either photosynthesis or krebs cycle from ADP + P(from NADPH). When ATP is available, huge amounts of energy are released when needed by slicing one P atom from ATP So that it can again become ADP and undergo lots of processes to become ATP again. So energy is added from tearing of Phosphate Atom due to tearing of phosphoanhydride bonds. This is possible because of process known as hydrolysis, when ATP is in equilibrium with water and some electrons. And the process of ADP becoming ATP is recharging and occurs in mitochondria.
The processes are hydrolysis and rechargeation, but most important process is Krebs Cycle, where all of this happens.
Critical period because they had fully developed their vision