b) Some vaccinations lose effectiveness over time. For instance, the vaccine for meningitis works for about five years before additional vaccination is required. In terms of specific immune system responses, why would a vaccine lose effectiveness over time? (4 points)​

3. draw a topographic map that displays the following features: (4 points each) a. the contour interval is 20 meters. b. the point of lowest elevation is 960 meters. c. the point of highest elevation is 990meters. d. there is at least one sinkhole or depression, at any elevation. e. there is at least one steep slope and one gentle slope.