Veins have all of the following characteristics: (choose 4) A)Large lumen (space inside the vessel)
B) Thick walls
C) valves
D) small lumen (space inside the vessel)
E) thin walls
F) one cell thick
G) low blood pressure

Which of the following types of pollution is most responsible for large numbers of deaths worldwide because of unsafe drinking water? (a) nutrient pollution (b) thermal pollution (c) pathogen pollution (d) sediment pollution

How do disease caused by bacteria and disease caused by viruses react to antibiotics?

What happens to a food web when deforestation occurs due to urbanization? how does it effect the carbon cycle? how does this relate to photosynthesis?