Answer:
Your nails can help determine the oxygen supply throughout your body because it has an affect on your life. Blue fingernails are caused by a low level or lack of oxygen circulating in your red blood cells. This condition is known as Cyanosis.
Explanation:
This means that there is not enough oxygen in your blood
What i don’t get the question
The psychologist is using a Token Economy because for doing something, you get a reward in exchange.