Give below are few statements. Mark the statement which is not correct.

Options

A. Atoms are neigther created nor destroyed in a chemical reaction.
B. Law of definite proportion state that a given compound always contains exactly the same proportion of elements by weight.
C. Gay Lussac's law of chemical combination is valid for all substances.
D. A pure compund has always a fixed proportion of masses of its constituents.

Explanation

To determine which statement is incorrect, we will analyze each statement one by one.

### Step 1: Analyze the First Statement
**Statement:** Atoms are neither created nor destroyed in a chemical reaction.

**Analysis:** This statement is true. It is based on the law of conservation of mass, which states that in a chemical reaction, the total mass of the reactants is equal to the total mass of the products. Atoms are simply rearranged during the reaction.

### Step 2: Analyze the Second Statement
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