Sixty-five nations sign a treaty pledging caps on industrial emissions and the development of renewable resource energy production. which of the following would be a long-term positive externality for global health?
a. increased land allocation for wind farms
b. lower rates of childhood asthma
c. more manufacturing of vaccines
d. reduction of vitamin deficiencies in children

b. Lower rates of childhood asthma.

The text states that the treaty pledges a cap on industrial emissions and the development of renewable resource energy production. It does not state that  this energy will come from wind farms, so we cannot assume that A is the answer. The statement also has no connection to vaccines, nor does it state anything about vitamin deficiencies. However, we do know that a consequence of industrial emissions is the development of respiratory problems on the population. Therefore, B is the best answer.