6. Why might failure to move mucus create a problem?
- pathogenic organisms (germs can multiply and cause infection or illness
- sticky mucus clogs up the lungs so that oxygen finds it hard to pass through
- mucus traps pathogens (germs) by sticking to them and keeping them in the bronchi
7. In humans how are substances transported to all distant parts of the body?
- through the bloodstream
- through the respiratory system
- through the nervous system
8. which of these animals would have the largest surface area to volume ratio?
- horse
- hippopotamus
- tiger
9. which of these pairs of organs enables rapid exchange?
- Liver and Stomach
- Kidneys and capilleries
- Heart and lungs