How is the exposure rate generally expressed?
a. in roentgens per hour
b. in gray
c. in radiation absorbed dose
d. in microcurie

a. in roentgens per hour  

Explanation:

Exposure rate is the ratio of radiation exposure per unit of time. It is often used to measure radiation fields in the environment of a radioactive facility for exposure prevention and control. Exposure rate is generally expressed as per hour roentgens (R / h) used for X-ray or Gamma in air.

The röntgen or roentgen (R) is a unit of exposure to ionizing radiation. The name was given as a tribute to the German physicist Wilhelm Conrad Röntgen (or Roentgen) (1845-1923) who discovered X-rays.

multiple allele inheritance is traits controlled by more than 2 alleles (ex: pigeons having 3 alleles of one gene govern their feather color).