The correct answer is A. Release of adrenaline by the adrenal glands
Explanation:
The "fight or flight" response is a natural response to a possible threat or attack. During this, the endocrine system and more specifically the adrenal glands react by releasing substances such as adrenaline, noradrenaline, and other hormones. These substances make the body to be alert and prepare to either scape and avoid the threat (flight) or face it (fight). Additionally, this response has also multiple effects in the body that includes the dilatation of the pupils, an increase in the heart and breath rate, and trembling; however, once the threat disappears the body goes back to a normal state. According to this, during the "fight or flight" response in the endocrine system adrenaline is released by the adrenal glands.
