Question

the property of the product are different from those of its constituents state whether this statement best describes an element or compound or mixture

Answer 1

compound. because compound is formed by joining 2 or more elements that are chemically bonded. Compounds are totally different from its constituencies.

Answer 2

The answer to your question is compound. As compounds have the property of being totally different from their constituents. The best example that helped me a lot to understand this concept is
Water, i.e H2O
Hydrogen and oxygen are both gases but their resultant is a liquid.
Hope it helps. Best of luck