Which one of the following is a genetically transmitted character?

Select the incorrect statement from the following.

Which gene is lethal in maize?

Consider the following statements regarding the $ABO$ blood group in humans:
$I.$ It is controlled by multiple alleles.
$II.$ It shows codominance.
$III.$ Codominance can be manifested phenotypically in humans.
$IV.$ It follows Mendel's law of inheritance.
Which of the following statement$(s)$ are correct?

Genes that are similar in phenotypic effect when present separately,but together interact to produce a different trait and the ratio is $9:7$ in the $F_2$ generation. What are such genes known as?

How many types of zygotic combinations are possible between a cross $Aa \; BB \; Cc \; Dd \times AA \; bb \; Cc \; DD$?