a. The rock cycle is the only mass-transfer cycle on the Earth. b. A biogeochemical cycle involves only physical components. c. The carbon cycle is an example of a purely geochemical cycle. d. The hydrologic cycle involves reservoirs above, below, and at the Earth's surface.

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