Wolf cubs born in northern woods will grow thicker fur than wolf cubs born in southern woods.This research hypothesis is an example of a ______.

A) directional hypothesis
B) nondirectional hypothesis
C) null hypothesis
D) mutual hypothesis

This is a directional hypothesis because it predicts that the thickness of fur will increase in one specific direction (from north to south). A nondirectional hypothesis would simply state that there is a difference in fur thickness between cubs from the two regions, without specifying which direction the difference might go. A null hypothesis would state that there is no difference in the fur thickness of cubs from the two regions. A mutual hypothesis is not a recognized term in scientific hypothesis testing.