Chlorofluorocarbons (cfcs) are a problem because they

a. have been released in large quantities in the past
b. break down to reactive free chlorine atoms
c. attack ozone molecules in the upper atmosphere
d. all of the above

i know its c and a is pretty much true but i am really not sure about b so i don't know if it is d or just c.

The diagram shows the results when two parents are crossed. the letters represent alleles for a trait that is controlled by three different genes. which best describes this inheritance pattern? multiple allele because a trait is controlled by three different genes polygenic because the offspring have alleles from both parents multiple allele because the offspring have alleles from both parents polygenic because a trait is controlled by three different genes