Oxytocin is a hormone found in mammals that is associated with bonding, empathy, and trust. Testosterone is also a hormone, but it is associated with sexual development in males. Dopamine and endorphins are both associated with positive feelings, but they are types of neurotransmitters—a different type of chemical messengers—not hormones.

The pituitary gland activates other glands in the endocrine system by releasing hormones. It also releases hormones that are resonsible for growth; sometimes the pituitary gland is known as the "master gland".

The adrenal glands, which lie on top of the kidneys, are responsible for releasing epinephrine and norepinephrine—both hormones that are present in the "fight or flight" response. These hormones are responsible for the increase in blood pressure, blood sugar, and heart rate. In a simpler sense, they help produce the means and conditions necessary to generate a surge of energy for quick expenditure in times of impending peril.

The pineal gland secretes serotonin by day and converts it to melatonin at night. These chemicals affect mood, anxiety, and sleep. The pineal gland may also play a role in seasonal affective disorder, in which people are depressed during the darker days of winter. Selective serotonin reuptake inhibitors (SSRIs) are a class of drug that work to elevate mood by blocking the cells that breakdown serotonin, leaving it in the synapses of the nervous system for a longer period of time.

Dopamine has a neuromuscular function, as an absence is associated with Parkinson's disease. Norepinephrine has a stimulatory effect. Acetylcholine stimulates muscle cells to contract. Endorphins are the body's natural pain relievers.

The pituitary gland is considered the "master gland" of the endocrine system. Hormones secreted from the pituitary gland help regulate growth, metabolism, and numerous other bodily functions and processes. The medulla oblongata is the part of the brainstem located just above the spinal chord.

"Eating a snack," specifically one filled with carbohydrates would introduce sugar into the body. After being absorbed into the bloodstream, the levels of glucose in the blood would rise to normal blood glucose levels. All other answer choices do not include a resolution to rectify low blood sugar levels.

Hyperthyroidism also causes a reduced attention span and can lead to long-term neurological problems, and is typically treated with medication and (when necessary) surgical intervention. Hyperthyrodism can often result in a loss of necessary body weight, as opposed to weight gain. Hypothyrodism can result in weight gain.

Alzheimer's disease is cause by low levels of Acetylcholine in some parts of the brain. This neurotransmitter is responsible for alertness, aggression, and other emotions.

The pituitary gland is also known as the “master gland” and is controlled by the hypothalamus. It is a crucial component of the endocrine system. The pituitary gland is responsible for the release of growth hormone, which stimulates physical development. It also releases oxytocin, allowing for contractions during birth and milk flow for nursing. The pituitary secretes oxytocin during pair-bonding interactions; therefore, the pituitary gland also plays an important role in the development of group cohesion and social trust. Last, the pituitary gland is also known to give secretions that will stimulate the release of hormones in other endocrine glands.

The hypothalamus is responsible for control of hunger, thirst, body temperature, and the endocrine system. A person experiencing issues associated with the expression and regulation of the endocrine system would most likely have an issue associated with their hypothalamus.