The correct answer is that the population of foxes will also decrease in size.
The population of the fox is majorly dependent on the population of mice as the source of their food, and due to a fatal disease infecting the mice population, the population of the fox who majorly consumes mice would also get infected with the same deadly disease.
This condition will eventually result in declining of fox population due to their over-dependence on mice as the source of food.
Yes capital letters are generally the dominant alleles while lowercase are recessive alleles. RR would be homozygous dominant, rr would be homozygous recessive and Rr would be heterozygous taking on the phenotype of the dominant
