Answer:
A callus is a hardening of skin, keratin is the protein which is abundant in callus. Skin is a protective layer against a external environment. Outer layer of skin consist of keratin which is also found in hair. Callus is the accumulation of dead cells result due to friction and pressure exerts on the part in which they are present. The keratin component (keratinocytes) remains undifferentiated in these dead cells which causes hardening in callus.
The top of the Stigma is sticky and is where the pollen attaches to it.
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Solving problems with science means that to solve the problem the scientific method is used. This method includes observing, research, hypothesis , test and conclusion with a help of lot high level theory.
Without science there is not strict process to follow in order to resolve the problem end get to a solution.