Long neck of Girraffe or camel due to `:-`

Long neck of Camel of Giraffe has

Long neck of giraffe is an example of Lamarrckism.

What is the reason for long neck of giraffe. Name the theory based on this

What is the relationship between the long neck of Giraffes and its food ?

Long neck of camel is due to

Long neck of camel is due to

Long neck of giraffe is stabilized in its evolution by

Long neck of giraffe is stabilized in its evolution by

Assertion (A ) : The long neck of giraffe is due to centripetal selection. Reason (R ) : During directional selection when the mean value of phenotype coincide with new optimum environmental conditions. Centripetal selection takes over.