Milk secretion and beard growth,both the traits are

The reason for the difference in genetic makeup in each animal species is:

The phenotype of an individual may be affected if the modified allele produces:
$(a)$ No enzyme at all
$(b)$ The normal/less efficient enzyme
$(c)$ $A$ non-functional enzyme

Assertion $A$: Gene is the unit of inheritance.
Reason $R$: The properties of tissues are due to the constituents of their cells.
Which option is correct for Assertion $A$ and Reason $R$?

Example of intergenic gene interaction is/are

Read all the given statements carefully and determine the number of correct statements.
$(1)$ Mutations are not hereditary.
$(2)$ Male $Drosophila$ flies do not show crossing over.
$(3)$ In honeybees,the male bee is diploid.
$(4)$ In a frame-shift mutation,one nitrogen base is replaced by another nitrogen base at a specific position.
$(5)$ Genes are responsible for inheritance.