Every weekend in summer, large numbers of people leave the hot desert climate of phoenix to head for vacations in the cooler climates of northern arizona. this is an example of
a. permanent migrationb. cyclic movementc. intervening opportunitiesd. commuting

Which of the following statements is true? a. there is not enough food produced in the world to feed everyone. b. the biggest cause of hunger and malnutrition is the cost of getting food to people who need it most. c. most countries have enough arable land and resources to feed their own population and export a surplus d. malnourishment is only seen in a few countries with very limited food supplies.

Which of the following is not a pillar of the nuclear proliferation treaty? nonproliferation reduction of nuclear weapons by 85-90% right to peacefully use nuclear power disarmament

Which revelation resulted from the observation of the spectrum of different galaxies? a. there were more galaxies whose spectrum was blueshifted b. there were no galaxies whose spectrum was redshifted c. there were more galaxies whose spectrum was redshifted d. there were no galaxies whose spectrum was blueshifted