Jeff lives in the United States, and he recently flew to Spain. Even after sleeping for several hours on the flight, he still felt lethargic for a few days. If Jeff has not caught an illness, which of the following is the
most likely explanation for his physical response?

30 a town is built on the banks of a small lake on the edge of a desert. after some time, the townspeople discover that water from the lake has become too polluted to use. describe one way that the lake may have been contaminated by the actions of the townspeople, and explain how the townspeople can remediate this problem.