Melatonin is a molecule that is produced in the pineal gland and secreted into the blood. melatonin then travels to different parts of the brain. it causes drowsiness and decreases body temperature to assist in the regulation of the sleep/wake cycle. what kind of control is used to regulate this molecule? a. muscular control, because the muscles can be used to control the release of melatonin b. neural control, because the brain sends the signal to release melatonin through nerve cells c. cardiovascular control, because melatonin flows through the blood to deliver the message d. endocrine control, because melatonin is secreted into the blood and regulates body processes

The answer is D.

Melatonin is a molecule that is produced in the pineal gland and secreted into the blood. Melatonin then travels to different parts of the brain. It tells the brain and the rest of the body about the time of wake and sleep. It causes drowsiness and decreases body temperature to assist in the regulation of the sleep/wake cycle. The melatonin secretion into the blood is regulated by the endocrine system, by the hypothalamus which on gets stimulated by the light.

The correct answer is option D which is that endocrine control can control melatonin.

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.