Answer:
i cant read it but its c and a
Explanation:
my thinking faces
Answer: Option (d) is the correct answer.
Explanation:
A reaction in which there occurs change in oxidation state of reacting species is known as an oxidation-reduction reaction.
(a)
Will be written as:

In this reaction, there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(b) 
Will be written as:

Similarly here, there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(c) 
Will be written as:

Here, also there occurs no change in oxidation state of reacting species. Hence, it is not an oxidation-reduction reaction.
(d) 
So, here there occurs change in oxidation state of Mg from 0 to +2 and oxidation state of H changes from +1 to 0. Hence, it is an oxidation-reduction reaction.
Thus, we can conclude that
is an oxidation-reduction reaction.
Answer:
The process of making S'more by adding chocolate bar, gram-crackers, and marshmallows in layers is not a chemical reaction
Explanation:
In a chemical reaction, the substances involved in the reaction are known as the reactants and the substances produced have different physical and chemical properties than those of the reactants and they are known as the products.
The bonds that hold the atoms of the reactants are broken down and rearranged, creating entirely new substances as products. Therefore, energy must be added and/or evolved in any chemical reaction and all reactant atoms should be involved in the reaction.
The change in energy can be sensed as heat change such as increase or decrease in the temperature of the products
Since S'more does not involve any of the above changes that occur in a chemical reaction when the chocolate bar, gram-crackers, and marshmallows are put together, it is not a chemical change or a chemical reaction.
Answer:
31.64...
Explanation:
The formula is volume is equal to mass over density.
So 25/0.79=31.64...