According to $Darwin$,fitness refers to .....

$A$ population splits into two or more groups and these groups occupy different ecological zones. This is known as:

In a species,the weight of newborn ranges from $2$ to $5 \; kg$. $97 \%$ of the newborns with an average weight between $3$ to $3.3 \; kg$ survive,whereas $99 \%$ of the infants born with weights from $2$ to $2.5 \; kg$ or $4.5$ to $5 \; kg$ die. Which type of selection process is taking place?

According to Hugo de Vries,the mechanism of evolution is

According to Hugo de Vries,speciation due to mutation is saltation,which means-

Which factors contribute to the success of organisms with variations?