Which activates a convection current, starting the flow of a fluid? a. cold temperatures at the north pole b. heated liquids at earth's surface c. iron-rich rocks in the mantle d. temperature differences in the mantle

Find lake kissimmee in the middle of the state. into what river does the lake drain?

Air masses are characterized by various properties including temperature humidity air temperature pressure and wind speed . which of the following air masses is associated with low relative humidity and high temperature

These factors threaten north americas ecosystems