Its<span> a nuclear process used for determining the concentrations of elements in a cast amount of materials.</span>
Answer: The correct option is A.
Explanation: In a chemical reaction, reactants react to form a number of products.
For the formation of products, the bonds of the individual reactants must be broken and the bonds of the products must be formed.
For example: Formation of water from hydrogen gas and oxygen gas. Reaction follows:

The Bonds of hydrogen and oxygen molecule are broken and new bonds between hydrogen and oxygen atoms are formed to give water molecule.
Answer: C
Explanation: A lunar month is 29.53 earth days. Since an earth calendar as only integer days, it could be either 29 or 30 days later.