Pinacoids must combine with another crystal form to make a crystal, and often form the top and bottom of prismatic crystals. plutonic -. formed of magma cooled beneath the Earth's surface. polymictic -. a conglomerate or breccia which has clasts of different rock types.
As the sun heats the ground or ocean, warning them, the air near the ground or ocean warms and becomes less dense As this happens the air begins rising, which lowers the air pressure at the Earth's surface. A large area of low pressure created this way is called a thermal low.
Report Abuse. Air pressure is the is pressure of air pressing down on the surface of the earth. High pressure is cold air falling to take the place of warm air rising. Low pressure is warm air rising leaving behind lower pressure when the air faling is still a bit warm.