Select incorrect statement

$(A)$ Linked genes cause absolute lethality
$(B)$ Persons affected by $PKU$ do not show mental disorder
$(C)$ $F_{2}$ ratio in codominance and incomplete dominance are same
$(D)$ Sex of male Drosophila is dependent on $Y-$chromosome

Which of the following pairs is $wrongly$ matched?

Which of the following characteristics represent ‘Inheritance of blood groups’ in humans?
$(a)$ Dominance
$(b)$ Co-dominance
$(c)$ Multiple allele
$(d)$ Incomplete dominance
$(e)$ Polygenic inheritance

Pick out the correct statements.

$(1)$ Haemophilia is a sex­linked recessive disease.

$(2)$ Down’s syndrome is due to aneuploidy.

$(3)$ Phenylketonuria is an autosomal recessive gene disorder.

$(4)$ Sickle cell anaemia is an $X$-­linked recessive gene disorder.

Choose correct answer :

$(i)$ Queen Elizabeth shows a number of haemophilic descendents.

$(ii)$ Variation in blood group prevalences due to incomplete dominance.

$(iii)$ Drosophila has three pairs of autosomal chromosomes.

$(iv)$ In birds, female is heterozygous.

Which of the following is true about linkage

$I.$ It is phenomenon in which more recombinants are produced in $F_{2}$-generation

$II.$ More parental combination are produced in $F_{2}$-generation

$III.$ Genotype which are present in $F_{1}$ hybrid. Reappear in high frequency in $F_{2}$-generation

$IV.$ It is a phenomenon in which two chromosome are linked