A seesaw is an example of a first class lever The fulcrum, which is the part of the lever that does not move, is in the middle. The resistance, which is the weight (person) you are trying to lift is at one end. The effort, which is the force applied to the lever, is the person sitting on the other end.
The Hanahaki Disease is a disease in which a person grows flowers from their lungs because of unrequited love.
In a more detailed example: “Hanahaki Disease (花吐き病) is a fictional disease in which the victim coughs up flower petals when they suffer from one-sided love. It ends when the beloved returns their feelings (romantic love only; strong friendship is not enough), or when the victim dies. It can be cured through surgical removal, but when the infection is removed, the victim's romantic feelings for their love also disappear.”
B cells and T cells are examples of a lymphocytes.
Food and Drug Administration
