Artificial selection to obtain cows yielding higher
milk output represents :
(1) stabilizing followed by disruptive as it stabilizes
the population to produce higher yielding cows.
(2) stabilizing selection as it stabilizes this
character in the population.
(3) directional as it pushes the mean of the character
in one direction.
(4) disruptive as it splits the population into two,
one yielding higher output and the other lower output.