Question

______ is a deadly, colorless, odorless gas that is a by-product of incomplete combustion. cadmium hydrogen peroxide sulphur carbon monoxide

Explanation:

Cadmium is a metal (not a gas), Hydrogen Peroxide is a liquid compound, Sulphur is a solid non - metal. Carbon Monoxide (CO) is a colorless, odorless gas formed during incomplete combustion of carbon - containing substances and is deadly due to its ability to bind with hemoglobin.

Answer:

D. Carbon Monoxide