【单选题】

Penguins live together in large and busy colonies.Every pair has a little piece of grounD、When a penguin wants to walk through his neighbor’s ground he must ask for permission. If he does not, he will have to fight.

Penguins come and go all day. They fight, fish and look after their children. (33) All penguins are good parents--the emperor penguins are perhaps the best parents in the worlD、 They walk in from the sea in the middle of the darkAntarctic winter. They choose their wives in the dark. They can only hear them--not see them. Then the females lay their eggs and go away for two months. The males look after the eggs. They hold them on their feet inside a fold of skin. If the eggs get cold there will be no chicks. There is no fooD、The snow falls. The wind blows-sometimes at 150 kilometers an hour. The penguins do not move. When the females return from the sea they will not remember their husbands. It does not matter. Only one thing matters-the eggs.Emperor penguins never fight-unless a penguin leaves a chick for a minute. Then they fight because they all want it. They are strange and wonderful birds.
What is very important is______.
A、female penguins B、male penguins
C、eggsD、a piece of ground