Tham khảo tài liệu 'anh ngữ sơ cấp - học tiếng anh bằng hình ành (phần 3) part 1', tài liệu phổ thông, tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | There may be as many as 100 000 different sorts of proteins in a man s body at work in as many different ways. It is a protein in our blood which takes up oxygen from the aữ we breathe into our lungs and carries it to the cells which need it It is another protein which makes our bones strong and another which makes our muscles able to pull on and move our bones. It is other proteins in our hair and skin and nails which make them what they are. Others again do very important work in the digestion of food in controlling other changes in the body in keeping it healthy and in making children become so surprisingly like their parents. noil finger noil toe nail. Our nails aru living parti of u . dlgectioru the changing of food In the Booth and nlOBach no that BOteriab In the food Bay bo used by the body. 408 How do these very complex materials come into being The answer is through the work of plants. Plants need sunlight. This is common knowledge within the experience of most of us but you can show how hue it is if you make this little experiment Grow two bean seeds over glasses of water starting them in a dark cupboard. After a few days take one glass out into the daylight and keep the other in the dark. Compare the two from time to time. You will find that it is the plant in the light which grows a sưong stem and green leaves. within in inside. Not on opposite of without OS commonly used see page 32 . experience knowledge we get OS we go on living seeing what goes on and thinking about it. experiment getting knowledge by doing something so that you are able to watch what takes place and find what in the outcome is dependent upon what. bean common plant whose seeds and sometimes seed coverings are used far food. 409 In 1772 the Englishman Joseph Priestley the discoverer of oxygen made a most important experiment He knew from experience that ak is necessary to plants and animals. He knew that if you put a live mouse for example under a glass so that no fresh aừ can come
