Pieces of rock and sand settle to the bottom or sides of a river because: they are heavier than waterthey are lighter than watergravity is stronger in a river than on landwind blows the pieces to the bottom

Food can come from sustainable or unsustainable resources. why has the united nations suggested that bugs could be a better source of food than animals like pigs or cattle?

How much water is in the ocean in cubic kilometers

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