Points to Remember. 1  Marijuana refers to the dried leaves, flowers, stems, and seeds from the hemp plant, Cannabis sativa. 2  The plant contains the mind-altering chemical delta-9-tetrahydrocannabinol (THC) and other related compounds. 3  People use marijuana by smoking, eating, drinking, and inhaling it.
A cold front is symbolized on a weather map as a line with triangles. The triangles can be thought of as icicles. Cold fronts are often coloured blue. The presence of a cold front means that cold air is advancing and pushing underneath warmer air.
When two air masses meet, we get weather fronts, and the type of front depends on the type of air mass advancing. The differences in the air masses come from differences in air pressure, temperature, moisture and density. A cold front is when a cold air mass moves into the area of a stationary warm air mass.