B. Explain in a few lines.
1. What happens to food in the mouth?
2. What happens to food in the small intestine?
3. How do living beings get energy from food?
4. How does blood circulate in our body?
5. What happens to blood in the lungs?
Answers
Answer:
1)Saliva softens and moistens food and washes over TASTE BUDS in the tongue so that flavors can be identified
2)The digested food is absorbed inside the small intestine which have finger like projections called villi in its inner wall.
3)Organisms mainly use the molecules glucose and ATP for energy. ... The flow of energy through living things begins with photosynthesis, which creates glucose. In a process called cellular respiration, organisms' cells break down glucose and make the ATP they need.
4)Blood comes into the right atrium from the body, moves into the right ventricle and is pushed into the pulmonary arteries in the lungs. After picking up oxygen, the blood travels back to the heart through the pulmonary veins into the left atrium, to the left ventricle and out to the body's tissues through the aorta.
5)Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs. Blood leaves the heart through the aortic valve, into the aorta and to the body.