Amajor side effect that stress can cause on the gastrointestinal system is a. diminished levels of gastrin

elevated level of cortisol causing overeating

Explanation:

The stress affects the gastrointestinal system negatively in a number of ways and thus imbalance the normal functions. The low oxygen and flow of blood, cramps can be caused by stress. The stress response allows the signal to adrenal gland by nerves and hormone. The adrenal gland secretes cortisol and adrenaline.  

The elevated level of cortisol allows the body to demand for food and fats. Thus, this increases the craving for eating food. So, a major side effect that stress can cause on the gastrointestinal system is elevated level of cortisol causing overeating.

answer; i believe that the correct answer is; ///bodies of water store heat during the day and release it at night;

a. the production of carbon dioxide through the process of photosynthesis