Which substance can be broken down by chemical means

1. Ammonia  

Step-by-step explanation:

Ammonia, NH₃, is a compound of nitrogen and hydrogen.

Thus, it can be broken down by chemical means into the elements nitrogen and hydrogen.

The other options are wrong, because Al, Sb, and Pb are elements. They cannot be broken down chemically into simpler substances.

answer7,570,82356 cubic centimeters;