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.

Which statement about relative potential energy of electrons is correct? a. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 2 s orbital of the second electron shell. b. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 3 p orbital of the third electron shell. c. an electron in the 3 p orbital of the third electron shell has more potential energy than an electron in the 2 p orbital of the second electron shell.