(2) Cereal food mainly provides us with sugar, which is the main energy-supplying substance for human physiological activities. The energy consumed by human life activities mainly comes from the oxidative decomposition of sugars, accounting for about 70% of human energy supply. The final product of sugar is glucose, which is easily soluble in water, absorbed by small intestine into blood circulation system, and finally transported to cells, where mitochondria breathe and provide energy for life activities.
(3) "Poor disease" is mainly caused by lack of vitamin A, "passerine" is night blindness, pig liver and fish contain vitamin A, and carrots and corn contain carotene, which can be converted into vitamin A in the body, so patients with "poor disease" can eat more pig liver, fish, carrots and corn.
(4) Healthy diet should pay attention to reasonable nutrition, that is, all kinds of nutrients ingested from food are in balance with the human body's demand for these nutrients, neither lacking nor excessive. According to the pagoda of balanced diet, five foods should be taken in a balanced way. Reasonable nutrition also includes reasonable dining system and reasonable cooking methods. Eat three meals a day on time. Teenagers are an important period of growth, and there is a great demand for protein, so teenagers should ensure comprehensive and reasonable nutrition.
So, the answer is: (1) two; Vitamin;
(2) sugar; Cell; Mitochondria; Energy;
(3) vitamin a;
(4) Pay attention to reasonable nutrition. The nutritional mix is reasonable and comprehensive, neither lacking nor excessive. According to the pagoda of balanced diet, eat five kinds of food in a balanced way. Eat three meals a day on time, with a ratio of 3: 4: 3. Pay attention to protein's intake.