He and his twin brother are as alike as two peas in a pod.

He and his brother are as alike as two peas in a pod.

He thinks that war is a necessary evil.

Do you understand the necessity of this project?

That information is unnecessary.

That information is completely unnecessary.

A transcendental function is a type of function that cannot be expressed as a solution to an algebraic equation.

An elementary function is one of the basic functions in mathematics.

Algebraic functions are a part of mathematics, and understanding them is important.

In quantum mechanics, the state of a particle is described by a wavefunction.