A warming climate thaws out frozen methane (a greenhouse gas) in Siberia, leading to further warming.

A species of plant goes extinct, and over time, another species of plant adapts to fill the extinct plant's ecological niche.

Plant and animal life slowly return to the slopes of a volcano following an eruption.

Invasive species are introduced to the Great Lakes via boat hulls, making it more difficult for native species to find enough food.

Labor contractions cause the release of oxytocin, which stimulates more contractions

Rise in blood glucose causes insulin secretion, which causes cellular uptake of glucose

The adrenocorticotropic hormone, released from the anterior pituitary, causes the release of cortisol from the adrenal glands, which inhibits the anterior pituitary from releasing more adrenocorticotropic hormone

Hot temperature causes the blood vessels in the skin to dilate and sweat glands secrete sweat to decrease the body's temperature back to normal

Low blood volume leads to the release of aldosterone, a hormone that causes sodium and water reabsorption to increase the blood volume

Oxytocin causes uterine contractions, which cause more release of oxytocin

Body temperature rises and causes sweat glands to open up and reduce body temperature

Hunger causes metabolism to slow down, which reduces hunger

Blood pressure rises, which causes vasodilation to lower blood pressure

Blood sugar rises, which causes the body to release insulin, which lowers blood sugar

Blood clotting

Blood sugar levels

Thermoregulation

Blood osmolarity

Blood pressure

Oxytocin

Insulin

Antidiuretic hormone

Calcitonin

Glucagon

positive feedback

equilibrium

negative feedback

feedback inhibition