Which of the following are considered pure substances? element compound homogeneous mixture heterogeneous mixture

element and compound.

Explanation:

reason

an element is a pure substance that cannot be broken down into simpler substances by any ordinary physical or chemical process.

and compound is a pure substance that consists of two or more elements held together in fixed proportions by natural forces called chemical bonds.

homogeneos and heterogenous mixtures are considered impure substances because they dont have a definite composition.

indium, and thallium have three electrons i think

the answer would be c