His is the term used to describe an argument or proof which is logically correct. that is, its conclusion follows from its assumptions or premises.

Valid

Explanation:

The term "valid" generally refers to a property of particular statements and deductive arguments. This term is used to describe an argument or proof that is logically correct. That is, its conclusion stems from its assumptions or premises.

A valid argument is one that the conclusion necessarily follows from the premises. That is, if the premises are true, the conclusion will also be true.

Suppose you are presented with two true premises. If you accept that both are true, then you will have to accept that the conclusion is also true, because there is no possibility that the conclusion is false in this case.

"a.) well–developed vascular system."