B3.2

1. The layer of tissue between the epidermis and the vascular bundle.
4. Structures in the heart and veins that prevent the backflow of blood.
5. The blockage of an artery, often leading to a heart attack.
8. The arteries that supply the heart muscle itself with oxygen and nutrients.
10. The two lower chambers of the heart that pump blood out to the body or lungs.
12. The outermost layer of cells in a plant providing protection.
14. The two upper chambers of the heart that receive blood.
16. The tissue that transports organic compounds like sugars from source to sink.
17. The largest artery in the body that carries oxygenated blood from the left ventricle.

2. The loss of water vapor from the leaves and stems of plants.
3. Blood vessel with valves that carries blood back to the heart at low pressure.
6. The buildup of fatty tissues in the artery walls causing them to narrow.
7. The tissue that transports water and minerals from roots to leaves.
9. Thick-walled blood vessel that carries blood away from the heart at high pressure.
11. Small pores in some capillary walls that allow for high permeability.
13. Pores on the underside of a leaf that allow for gas exchange and water loss.
15. The smallest blood vessel with one-cell thick walls for exchange of materials.