<u>Answer:</u> The equations are provided below.
<u>Explanation:</u>
Skeleton equations are defined as the equations which simply indicate the molecules that are involved in a chemical reaction. These equations are unbalanced equations.
Balanced equations are defined as the chemical equation in which number of individual atoms on the reactant side must be equal to the number of individual atoms on the product side.
Water decomposes in the direct current to form hydrogen and oxygen.
Skeleton Equation: 
Balanced Equation: 
Mercury (II) oxide decomposes in heat to form mercury, oxygen.
Skeleton Equation: 
Balanced Equation: 
Calcium carbonate when heated forms calcium oxide and carbon dioxide.
Skeleton Equation: 
Balanced Equation: 
Group 2 hydroxides, when heated forms oxide and water vapor.
Skeleton Equation: 
Balanced Equation: 
I would say #3 I’m sorry if it’s wrong tho
I found another question like this. Someone answered "The best answer to this question is adding a catalyst.
Adding a catalyst will cause the greatest increase in the rate of reaction for this chemical reaction , 8Zn(s) + S8(s) 8ZnS(s). ---> adding a catalyst always affects the rate of a reaction."
Th correct answer is option C. Calling can be hazardous because it also attracts parasites and predators.
The mating call is used by the males to attract females for sexual reproduction. By using vocal sounds males are not only making themselves attractive to females, they are also making themselves vulnerable to predators.
Thus the mating call can have a disastrous effect on the survival of the species.