science

4. in circulatory system where cells and blood come in contact
5. muscles pull it down, it expands to let air in
6. sacs in which co2 poor and o2 rich get converted to co2 rich and o2 poor
7. branches" tiny veins that carry air to the aveoli
8. type that carries the blood away from the heart
9. between contractions
10. that push food down in the esophagus, stomach, small intestine & large intestine
11. that only refers to water
14. to expand surface area

1. water concentration is lower outside the cell therefore the water moves outwards
2. the lining of the mouth and the teeth
3. of cells, 3 types, permeable, non permeable, semi permeable
12. in the digestive system, coming from certain organs.
13. air,moistens air & filters air