Who discovered epistasis?

Pattern baldness,moustaches and beard in human males are examples of

In poultry,the new comb colour that appears by the collaboration of two dominant genes is:

When the expression of one gene is inhibited by the factors of another gene,it is called.....

The coiling of the shell in the snail $Limnaea$ is an example of.....

In $Lathyrus$ $odoratus$,dominant genes $C$ and $P$ are required for the production of purple flower color. What will be the ratio of white to purple flowers in a cross between $CcPp$ and $Ccpp$?