Until the middle of the 20th century, doctors sometimes suggested that people smoke in order to reduce stress. Since then, doctors have been asking
patients who smoke to quit.
What caused this change?
A. Tobacco is an illegal drug, and doctors are required to discourage
its use.
B. Tobacco plants have been categorized as an endangered species.
C. Studies have shown that tobacco and tar in cigarettes have
negative health effects.
D. Tobacco is a nonrenewable resource, and the government has
restricted its use.

Not completely sure, but maybe C.?

Wetlands form where water and land meet. a lake with a wetland fringe can fill in with decayed plant and animal material to become a wet meadow. a pond can fill in to become a bog or fen. sediment can fill in a river marsh to become a swamp.flooding of coastal lowlands from rising sea levels has created broad coastal marshes that are protected from wave action by barrier islands or reefs. coastal wetlands also form when rivers deposit sediment as they reach the ocean. plants then take root and hold the soil firm against the forces of tides and waves.