Which of the following is not a reason why infectious diseases like malaria and hiv/aids often hamper economic development?
a. life expectancy begins to rise.
b. caregivers lose time at work.
c. more tax dollars are shifted to health care.
d. people have difficulty working and earning income

Explain the cause for movement river valley civilization to early industrial centers

Which of the following is evidence to the past existence of glaciers?

Some gamma ray bursts are hypothesized to come from mergers of neutron stars or black holes. if this hypothesis is correct, what else should we in principle be able to detect from such mergers? a. gravitiational waves b. x-ray bursts c. significant disruption of gas thousands of light-years away in the surrounding galaxy d. an "afterglow" of bright visible light, lasting for weeks