Answer: Pons (brainstem)
Explanation:
The pons is a part of the upper portion of the brainstem. It is responsible for controlling the breathing, regulates the sensation of the balance, taste and hearing.
The tumor in the pons region requires intensive treatment generally if the tumor growth continued in this region for an appreciable period of time this is likely to impact the functions like heart rate and breathing.
According to given condition, a tumor has been developed in pons region of brainstem which is affecting the fluctuations in the heart rate.
