Answer:
Nitrogen fixation
Explanation:
Certain soil bacteria, e.g., <em>Azobacter spp</em> can combine free nitrogen of the atmosphere with oxygen to form nitrates. This is called <u>nitrogen fixation</u>. Other nitrogen-fixing bacteria such as Rhizobium form symbiotic unions with the roots of leguminous plants called root nodules. They fix nitrogen to form nitrates which are used up by the host plant. Nitrifying soil bacteria, e.g., <em>Nitrobacter </em>convert nitrites to nitrates in a process called <u>nitrification</u>.
The green house effect occurs when carbon dioxide and water vapor form an invisible blanket around the globe that allows the sun's light to enter, but traps the heat. Green house effect is a process that warms the Earth's surface. When the sun's energy reaches the Earth's atmosphere, some of it is reflected back to the space and the rest is absorbed and re-radiated by greenhouse gases.
