Statement : 1 Mark each
The two laws of chemical combination are
1. Law of conservation of mass: 
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
2. Law of definite proportions:
The law of definite proportions, also called Proust's law or the law of definite composition, or law of constant composition states that a given chemical compound always contains its component elements in fixed ratio (by weight) and does not depend on its source and method of preparation.