Question

Think of the following:

Tears, sweat, saliva, milk, Insulin, urine.

What are these excretion or secretion ? Why?

Answer 1

Except urine, all others listed are secretions, because secretion is giving out by a cell or gland some substances that have some utility for the body. While excretion is the passing out of substances that have no further use in the body or are harmful.