Interspecific crosses are rare in nature and intergeneric crosses are almost unknown. Why?

Tjio and Levan's contribution is very significant because they

Match the following pairs based on the sex determination mechanism shown in the table:

	Male $(♂)$	Female $(♀)$
$x$	$XY$	$XX$
$y$	$ZZ$	$ZW$

In certain plant species,red flower colour is incompletely dominant to white flower colour (the heterozygote is pink) and tall stems are completely dominant to dwarf stems. If a tall pink plant $(TtRr)$ is crossed with a tall white plant $(TTrr),$ which one of the following types of plants would be produced in the offspring?

With the help of an example,differentiate between incomplete dominance and co-dominance.

State how many of the given statements are correct.
$(1)$ In a dihybrid cross experiment,Mendel obtained a test cross ratio of $1:1:1:1$.
$(2)$ Coupling and repulsion were first explained by Bateson and Punnett.
$(3)$ Klinefelter syndrome is a sex-chromosomal disorder occurring in females.
$(4)$ Mendel selected $7$ pairs of contrasting traits in pea plants to explain his experiments.
$(5)$ The chromosomal theory of inheritance was first proposed by Sutton and Boveri.