How many types of gametes will be produced by a $O$ Drosophila having following arrangement of
two genes ($y*$ and $w*$) on $X-$chromosome?

In Drosophila, long wing and broad abdomen characters are dominant over to characters vestigeal wing and narrow abdomen. A pure breeding Drosophila having long wings and broad abdomen is crossed with a pure breeding vestigeal-winged and narrow-abdomened Drosophila. Two of the $F_1$ individuals were crossed and the following results were produced in the $F_2$ generation Long wing, broad abdomen in $482$ Drosophila. Vestigeal wing, narrow abdomen in $154$ Drosophila. Which one of the following is illustrated by these results

Discuss in detail the contributions of Morgan and Sturtevant in the area of genetics.

Two genes $R$ and $Y$ are located very close on the chromosomal linkage map of maize plant. When $RRYY$ and $rryy$ genotypes are hybridized, then $F_{2}$-segregation wii show

In a certain plant, red flowers $(R)$ are dominant to white flowers $(r)$ and tallness $(T)$ is dominant to dwarfness $(t)$. A heterozygous plant $(RrTt)$ is backcrossed with a double recessive plant $(rrtt)$. If the gene loci for colour and size and situated very close together on the same chromosome, the expected percentage of offsprings could be approximately

 respectively