What is a substance that cannot be separated into simpler substances by physical or mechanical methods such as filtering, boiling, or sifting?

A crystalline solid
A sublimation
A pure substance ••
An amorphous solid

Correct me if I'm wrong

What is the flipping answer.

You are correct :)

I agree

A crystalline solid

A crystalline solid

what is the eeefing answer.

You are correct. The correct answer is a pure substance. A pure substance is a type of matter that has a definite composition and cannot be separated into simpler substances by physical or mechanical methods such as filtering, boiling, or sifting. It consists of only one type of atom or molecule. Examples of pure substances include elements, such as oxygen or gold, and compounds, such as water or table salt.