Here's why:
* Nitrogen Fixation: Nitrogen is the most abundant gas in the atmosphere, but plants can't directly use it in this form. Certain types of bacteria, called nitrogen-fixing bacteria, can convert atmospheric nitrogen into a usable form (ammonia, NH3).
* Nitrification: Other bacteria convert ammonia into nitrite (NO2-) and then into nitrate (NO3-), which plants can easily absorb through their roots.
* Denitrification: Some bacteria convert nitrate back into nitrogen gas, completing the nitrogen cycle.
Therefore, bacteria play a crucial role in making nitrogen available to plants and other organisms.
