Paraphrase the formation of invisible gas products (CO2 and H2O vapor) and a mass decrease compatible with full combustion would be considered qualitative proof.
a. The creation of unseen gaseous byproducts (CO2 and H2O vapor) along with a reduction in mass indicative of complete combustion can be regarded as qualitative evidence.
b. The development of imperceptible gas substances (CO2 and H2O vapor) alongside a decrease in mass, indicating thorough combustion, can serve as qualitative evidence.
c. Qualitative evidence includes the generation of invisible gas products (CO2 and H2O vapor) and a decrease in mass consistent with complete combustion.
d. Evidence of full combustion includes the formation of invisible gas products (CO2 and H2O vapor) and a reduction in mass.