[单选题]《关于严明党的纪律和规矩论述摘编》指出，党章就是党的根本大法，是全党必须遵循的__。( )
A.总准则
B.总规矩
C.总纪律
D.以上都是

We know that many animals do not stay in one place. Birds, fish and other animals move from one place to another at a certain time. They move for different reasons; most of them move to find food more easily, but others move get away form places that are too corwded.
When cold weather comes, many birds move to warmer places to find food. Some fishes give birth in warm water and move to cold water to feed. The most famous migration(迁移) is probably the migration of the fish, which is called “salmon”. This fish is born in fresh water but it travels many miles to salt water. Then it gives birth and dies there. In northern Europe, there is a kind of mouse. They leave their mountain homes when they become too crowded. They move down to the low land. Sometimes they move all the way to the seaside, and many of them are killed when they fall into the sea.
Recently, scientists have studied the migration of a kind of lobster(龙虾). Every year, when the season of ba
A. they are short of food
B. there is not enough space
C. it’s getting warmer in the low land
D. it’s getting coldier in the mountains