Why has the u. s. trade deficit grown so rapidly since the end of world war ii?
o
a. free trade has made it cheaper to produce products abroad rather
than making them in the united states
o
b. costly international environmental regulations have made
american manufacturers less productive.
o
c. trade organizations like opec have refused to provide the united
states with valuable natural resources.
o
d. globalization has forced the united states to lend huge amounts
of money to poorer countries.

What is the difference between an observational study and an​ experiment? choose the correct answer below. a. in an​ experiment, a treatment is applied to part of a population and responses are observed. in an observational​ study, a researcher measures characteristics of interest of a part of a population but does not change existing conditions. b. in an​ experiment, a treatment is applied to an entire population and responses are observed. in an observational​ study, a researcher measures characteristics of interest of an entire population but does not change existing conditions. c. in an​ experiment, a researcher measures characteristics of interest of a part of a population but does not change existing conditions. in an observational​ study, a treatment is applied to part of a population and responses are observed. d. in an​ experiment, a researcher measures characteristics of interest of an entire population but does not change existing conditions. in an observational​ study, a treatment is applied to an entire population and responses are observed.