Pituitary gland.
When you feel stress, the pituitary gland, at the base of the brain, increases its production of the hormone ACTH. This hormone tells the adrenal glands, found at the top of your kidneys, to increase their production of hormones. These stress hormones help you to concentrate, speed your reaction time, and boost your strength. Your hypothalamus also helps your body respond to stress.
Answer:An inherited, natural selection.
Explanation: Adaptation is the process through which living organisms develop mechanisms this mechanisms may be Inherited to enable them survive competition and other prevailing circumstances. Which can also be environmental, climatic factors etc.
Adaptation helps to ensure the principle of NATURAL SELECTION,where organisms which have been able to develop similar mechanisms or have natural mechanisms that has enabled them to survive the prevailing circumstances in the habitat.
Both of them have a shell with a living organisms with the valves and they both are form somewhere different
