闪点行动x在线观看:较简单的初中英语作文

Cells and Temperature

Cells cannot remain alive outside certain limits of temperature and much narrower limits mark the boundaries of effective functioning. Enzyme systems of mammals and birds are most efficient only within a narrow range around 37C;a departure of a few degrees from this value seriously impairs their functioning. Even though cells can survive wider fluctuations the integrated actions of bodily systems are impaired. Other animals have a wider tolerance for changes of bodily temperature.

For centuries it has been recognized that mammals and birds differ from other animals in the way they regulate body temperature. Ways of characterizing the difference have become more accurate and meaningful over time, but popular terminology still reflects the old division into “warm-blooded” and “cold-blooded” species; warm-blooded included mammals and birds whereas all other creatures were considered cold-blooded. As more species were studied, it became evident that this classification was inadequate. A fence lizard or a desert iguana—each cold-blooded----usually has a body temperature only a degree or two below that of humans and so is not cold. Therefore the next distinction was made between animals that maintain a constant body temperature, called home0therms, and those whose body temperature varies with their environments, called poikilotherms. But this classification also proved inadequate, because among mammals there are many that vary their body temperatures during hibernation. Furthermore, many invertebrates that live in the depths of the ocean never experience change in the depths of the ocean never experience change in the chill of the deep water, and their body temperatures remain constant.

My Family

There are five people in my family. They are my grandfather, my grandmother, my father, my mother and I .

My father is doctor. He works in Yueqing. He goes to work on foot everyday. My father is not very tall, but he is strong, he is very kind to his patients and he loves his work.

My mother is teacher. She works in a middle school in Yue Qing. She goes to work by car. She is a very good teacher in my eyes.

I am a student in Yueqing FLS. My school is very beautiful. There are many tall buildings, green tress, nice flowers in our school. We have wonderful teachers too. I like studying in my school.

My grandparents don’t go to work any more. They have retired. They stay at home everyday. In the morning they go to the park and do morning exercises. In the afternoon, they drink tea with their friends. In the evening, they enjoy themselves watching TV and reading newspapers.

We have a happy family. I can’t say how much I love it!