Anchor: The Darwinian advantage of having a shorter head, if any, remains unknown.
Entailed: Nobody knows what the benefits of having a shorter head are. 
Contradiction: The Darwinian advantage that comes along with having a shorter head is widely known. 
Contradiction: No thanks, I already know it's too long and I don't have the time.
Contradiction: Three girls are splashing in the water using their feet.
Contradiction: Our elderly enemy has  shown his face.
Contradiction: She hadn't heard him while she tinkered with a trinket on her breast.