As far as I know, the adrenal glands, when submitted under pressure such as the one described in the example, secrete a substance known as epinephrine which has the tendency of increasing the affected person's heart rate and breathing.
Answer:

Hope it helped,
Happy homework/ study/ exam!
Answer:
the roots are weak
Explanation:
because it can’t hold its weight
Answer:
Mitosis
Explanation:
Mitosis is a type of cell division in which a cell divides into two daughter cells each having the same number of chromosomes as the parent cell. It ensures that every body cell contains the same number of genes as the parent cell. The cell that have 78 chromosomes have undergone mitosis while the other cells that contain 39 chromosomes undergo meiosis.
Answer:
The respiratory system and the circulatory.
Explanation:
The respiratory system brings in the oxygen and the circulatory system brings all of the oxygen through out the body.