In which one of the following, complementary gene interaction ratio of $9: 7$ is observed?

In sweet peas,genes $C$ and $P$ are necessary for colour in flowers. The flowers are white in the absence of either or both the genes. What will be the percentage of coloured flowers in the offspring of the cross $Cc\ pp \times cc\ Pp$ (in $\%$)?

After crossing two plants,the male progeny is found to be sterile. This phenomenon is inherited maternally,and the cause lies in genes located in the ...

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

Lethal genes are:

When certain traits are inherited only from the mother,it is likely a case of .....