Final answer:
The rate at which respiration is occurring in a mammal can be indicated by the respiratory rate, which is controlled by the respiratory center in the brain.
Step-by-step explanation:
The rate at which respiration is occurring in a mammal can be indicated by the respiratory rate.
The respiratory rate is the total number of breaths, or respiratory cycles, that occur each minute. It can be measured by counting how many breaths a mammal takes in a given time period.
The respiratory rate is controlled by the respiratory center located within the medulla oblongata in the brain, which responds primarily to changes in carbon dioxide, oxygen, and pH levels in the blood.