Tjio and Levan's contribution is very significant because they

The number of chromosomes in the cells of bread wheat ($Triticum$ $aestivum$) indicates that it is ...... .

Which of the following is a placental mammal and not a marsupial?

In a diploid organism,the condition where one of the alleles in a pair is present is called.....

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.

Differentiate between a monohybrid cross and a dihybrid cross.