The scientists who were credited in the proposal of the cell theory is Matthias Schleiden and Theodor Schwann.
It is known as ISCHEMIA.
Ischemia occur when there is an hindrance in the flow of blood to a particular organ in the body. Because it is the blood that carry oxygen round the body, such an organ will not get adequate supply of oxygen. Ischemia is usually caused by blockage or narrowing of the arteries.
An example of this is to whether smoke cigarette or not. People smoke whenever they feel anxious with their activities but they were thinking that it is not a habit, but in the end, they will be used to it that is why they tend to forget how to live without smoking. This is the reason why they got addicted and to some serious problems with their health.
The epidermis. It's the first layer of skin.