In a species, the weight of newborn ranges from 2 to 5 kg.97 % of the newborn with an average weight between 3 to 3.3 kg survive whereas 99 % of the…

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