D is the answer.
On the left, there are 3 atoms of Ca, 2 atoms of Cr, 6 atoms of N, and 18 atoms of O.
On the right, there are 3 atoms of Ca, 9 atoms of N, 27 atoms of O, and 2 atoms of Cr.
The coefficients needed to balance the equation would be 2, 7, 4, and 6 respectively.
<h3>Balancing chemical equation</h3>
This requires that the number of atoms of each element is the same both on the reactant and product's sides.
Hence, the balanced equation of the reaction becomes:

Thus, the coefficient for each species would be 2, 7, 4, and 6 respectively.
More on balancing chemical equations can be found here: brainly.com/question/15052184
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Traits are determined by alleles.
Answer:
The mass of SO2 will be equal to the sum of the mass of S and O2.
Explanation:
This can be explained by the <em>Law of Conservation of Mass</em>. This law states that mass can neither be created nor destroyed. Knowing this, we can say that the reactants of a chemical reaction must be equal to the products.
In this case, the reactants Sulfur (S) and Oxygen (O2) must equal the mass of the product Sulfur Dioxide (SO2). Therefore, the statement <em>"The mass of SO2 will be equal to the sum of the mass of S and O2" </em>is correct.