The answer to the first question is a.
        
                    
             
        
        
        
Answer:
The herds have been declining in recent decades due to a complicated mix of factors including hunting, disease, diminished food availability, and climate change, the report explains.
 
        
             
        
        
        
<span>An atom that has gained or lost electrons is called an ion</span>
        
             
        
        
        
This is why natural selection acts on phenotypes instead of genotypes. A phenotype is an organism's physical traits, while a genotype is an organism's genetic makeup. This may sound counter-intuitive since the genetic makeup does get<span> passed on from generation to generation through reproduction.</span>
        
             
        
        
        
Answer:
-20 kcal/mol (It stays the same)
Explanation:
Enzymes will reduce the Gibbs free energy of activation, but will neither increase or decrease the free energy of reaction.
Enzymes means of activity is by decreasing the activation energy (Ea or ΔG✳) for a reaction. This in turn raises the reaction rate.
Free energy of reaction 
= free energy of product - free energy of substrate
The free energy of the product remains constant even without the enzyme. Hence, the enzyme would show no effect on the free energy of the reaction.
The attached image shows the effect of changes in enzyme concentration on the free energy.