I believe the answer is b. decomposition adds to the soils nutrients, therefore creating the environment of plant growth which gives off o2.
Answer:
D. geographic isolation.
Explanation:
As the Grand Canyon formed, it became a physical barrier to the mixing of squirrels from its northern and southern sides. Each squirrel population was confined to a single side. This type of separation is referred to as geographic isolation.
You didn't provide the reaction, but enzymes usually just help the reaction take place, often faster then it would in regular conditions. They are completely used up during the reaction and don't affect it in any other way, meaning they don't change the properties of the compounds.
Sorry here for the points !! Good luck