saliva
Saliva is a clear liquid that always keeps the mouth and tongue moist.
scab
A scab is a layer of dried blood that forms on the skin when you hurt yourself or are wounded.
scalpel
A scalpel is a small knife used by surgeons to cut into the skin and other parts of the human body when operating.
scar
When you are wounded your skin is left with a scar. After a while the wound may close, but a scar will remain there.
scientist
A scientist is a person who does science, and they typically work in laboratories, where they research and experiment.