Match the following:

Column – $I$	Column – $II$
$(1)$ Failure of cytokinesis	$(p)$ To study inheritance of particular traits
$(2)$ Trisomy of $21$	$(q)$ Polyploidy
$(3)$ Error of metabolism	$(r)$ Down's syndrome
$(4)$ Pedigree analysis	$(s)$ Phenylketonuria

Choose the correct option for the given descriptions:
$(i)$ The heterozygous female transmits the disease to the son.
$(ii)$ Change in the shape of the $RBC$ from biconcave disc to elongated sickle-like structure.
$(iii)$ Mentally retarded.
$(iv)$ Haemoglobin is not formed in the proper amount in the blood.

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

In an organism,pink spot is a sex-linked recessive trait and black hair is dominant to white. If a pink spotted black heterozygous female is mated to a white male which is not spotted,the phenotypic ratio of the offspring would be

In $F_2-$generation, genotypic and phenotypic ratios are the same in the case of $-$

Read the following statements carefully:
$(1)$ Ploidy is a structural chromosomal abnormality.
$(2)$ Hemophilia is an autosomal recessive disorder in which blood does not clot.
$(3)$ Recombination is one of the factors responsible for evolution.
$(4)$ Genetic mapping allows the determination of the specific location of a gene on a chromosome.
$(5)$ Snapdragon plant is an example of incomplete dominance.
$(6)$ $ABO$ blood grouping shows both dominance and codominance.
Identify the correct and incorrect statements from the given options.