Which event during cell division is responsible for the emergence of new characteristics in the next generation of organisms?

In which of the following can recombination be observed?

The theory of recombination of linked genes due to crossing over of chromosomes during the pachytene stage of meiosis was put forward by:

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 will show

Assertion: In case of incomplete linkage,linked genes show new combinations along with parental combinations.
Reason: In case of incomplete linkage,linked genes are separated by crossing over.

In maize, colored endosperm $(C)$ is dominant over colorless $(c)$ and full endosperm $(R)$ is dominant over shrunken $(r)$. When a test cross is performed on the $F_1$ generation, the following results are obtained:
Colored and Full = $45\%$
Colored and Shrunken = $5\%$
Colorless and Full = $4\%$
Colorless and Shrunken = $46\%$
Based on this data, what is the distance between the two non-allelic genes (in $units$)?