B.
Ozone is an example of a secondary pollutant as it is formed due to the effect of a primary pollutant.
Answer: The scientist will perform another investigation in order to find out the role of certain genes in disease resistance.
Explanation-
As per the information given in the question, a mice having mutation in ear depicts same pattern of resistance when compared to another mice having normal ears. This indicates that the genes responsible for resistance are not related to genes that result in ear formation.
Therefore, to find out the effect of diet on disease resistance in rats, the scientist will perform another investigation in order to find out the role of certain genes in disease resistance.
Answer:
Synthetic because it is not a natural resource or material
Answer: population
Explanation: Population - Limiting factors like the availability of food, water, and shelter can impact an organism.