Which of the following is NOT an example of an ecological study? Select one:

a.
The study of how hummingbirds pollinate certain shrubs

b.
The study of competition between hummingbirds and honey bees

c.
The study of muscle strength in hummingbirds

d.
The study of how air pollution impacts hummingbird shells

Which of the following is true? a. under the current unemployment insurance system, benefits replace about 90 percent of the typical worker's prior pretax earnings. b. high benefit payments to unemployed workers will tend to increase the rate of unemployment. c. if a system of personal savings accounts replaced the current unemployment benefit system, the unemployment rate would fall to zero. d. the rate of unemployment in the large european economies has been persistently lower than that of the united states due to their more generous unemployment benefits.