What is represented by R? How many are there?

r represents rockets, rooms, and righteousness

Explanation:

there are many things which r can represent, so depending on context, there r many rs

voluntary muscles are controlled by the cerebellum.

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation: