Nitrogen form Symbol Use in soils and plants; Dinitrogen (Atmospheric Nitrogen) N 2: Dinitrogen is the most common form. It makes up 78 percent of the atmosphere but cannot be used by plants. It is taken into the soil by bacteria, some algae, lightning, and other means. Nitrate: NO 3: Nitrate is the form of nitrogen most used by plants for growth and development.
Reacting when you hear the tornado sirens go off is key. Emergency officials want reaction to be instinctive, not a frenzy of confusion, when you hear the siren sound. You'll have two chances to practice when the sirens sound today. The first drill will happen between 10 and 10:30 a.m. when children are in school.
A series of tornado outbreaks in April and May have now killed more than 400 Americans. Officials in Joplin, which is still reeling from the tornado, say sirens went off about 20 minutes before the twister hit, but given the fluid situation on the ground, it's still not possible to know why so many people died.