12.Some animals sleep in winter because the weather can be very cold and it is difficult for them to find food.They can sleep for a long time.This kind of winter sleep is called "hibernation". If an animal moves about a lot,it needs food.Hibernating animals do not need to eat much because they are not moving about.Their hearts heat very slowly and they also breathe slowly.They find a place out of danger.Their body fat keeps them alive and warm. Some animals,such as bears,may wake up from their hibernation on warm winter days and then quickly go back to sleep again when they see the snow is still thick on the ground.When the weather becomes warmer in spring,the animals start to wake up and look for food. (1)Some animals hibernate in winter because
. A.they feel cold B.it isn't easy for them to find something to eat C.they are weak D.both A and B (2)If an animal moves about a lot,it needs
. A.the sunshine B.winter sleep C.food D.water (3)Hibernating animals don't have to eat much because
keeps them alive and warm. A.the sunshine B.their body fat C.bad weather D.their hearts (4)Some animals may
when they find the snow is still thick on the ground. A.eat some food B.wake up on warm winter days C.quickly go back to sleep D.both B and C (5)The word "hibernation" means