填空题

How Deer Survive Winter Like most of the wild animals, deer survive the cold winter by using energy stored in the summer and fall, usually in the form of (1) 1. ______ ______. They also spend (2)______energy in winter than in 2. ______ summer. Deer always give birth to their fawns in May or June. This is good (3)______, because it coincides with the time when 3. ______ plenty of new plants are available. The’ mother deer must have enough food both to meet the needs of their own bodies and to 4. ______ produce (4)______for their fawns. As the fawns grow, they become less and less (5)______on their mothers. As winter 5. ______ comes, deer’s hair becomes darker and (6)______. Besides, 6. ______ nature provides another (7)______to help them survive the 7. ______ cold weather. They become somewhat slow and drowsy. Their heart rate (8)______This is an internal physiological 8. ______ response which is to (9)______their cost of energy. 9. ______ All these practices and responses that increase deer’s chances of survival in winter are the result of thousands Of years of (10)______. 10. ______