Which of the following structures is identical in monozygotic twins?

In hexaploid wheat, what are the haploid $(n)$ and basic $(x)$ chromosome numbers?

In maize, albinism is caused by the effect of:

Match the items of column $I$ with column $II$:

Column $I$	Column $II$
$(a) XX-XO$ method of sex determination	$(i)$ Turner's syndrome
$(b) XX-XY$ method of sex determination	$(ii)$ Female heterogametic
$(c)$ Karyotype $45$	$(iii)$ Grasshopper
$(d) ZW-ZZ$ method of sex determination	$(iv)$ Female homogametic

Select the correct option from the following:

$Statement A$: For a particular character in an individual,each gamete gets only one allele.
$Statement B$: Chromatids of a chromosome split (separate) and move towards opposite poles during anaphase of mitosis.

Which of the following statements are correct?
$i$. $X$ chromosome has a large amount of euchromatin.
$ii$. Heterochromatin is genetically inert.
$iii$. Both $X$ and $Y$ chromosomes are homologous.
$iv$. Crossing over does not take place in sex chromosomes in females.
Choose the correct option.