In what form do most plants absorb nitrogen from the soil?

✅Explanation:
Most plants primarily absorb nitrogen from the soil in the form of nitrate (NO3). Nitrate is a highly soluble form of nitrogen and is readily available for plant uptake. While plants can also absorb ammonium (NH4), nitrate is typically the preferred form because it is more easily assimilated in the majority of plants and is less toxic compared to ammonium.

📌Other Options Explanations:
-A. NO2 (nitrite): Nitrite (NO2) is an intermediate form of nitrogen in the nitrogen cycle. Nitrite can be toxic to plants if it accumulates.
-C. NH4 (ammonium): Although some plants can utilize ammonium, nitrate is the more dominant form for most plant species. (rice, potato). Excess ammonium can lead to toxicity and acidification of the soil.

🛑 Additional Information::
-Plants cannot directly use free nitrogen gas, also known as molecular nitrogen. Prior to use, it must be fixed into nitrogenous compounds.
-The majority of plants take nitrogen as NO3 (nitrate) or NH4+ (ammonium ion).
-The most essential source of nitrogen for plants is nitrate.
-Dead plants and animals, excretion of nitrogenous wastes are converted into nitrites by the action of bacteria present in the soil.
-Some bacteria can even convert nitrites into nitrates that can be used again by green plants.
-There are still other types of bacteria capable of converting nitrates into free nitrogen, a process known as denitrification.
-It can build up in the cell sap of a variety of plants and contribute to the production of osmotic potential. Plants, on the other hand, cannot use it as such.
-It is converted first to nitrite (NO2-), then to ammonia (NH3+).
-Ammonia then reacts with organic acids to form amino acids, which can subsequently be used to make a variety of nitrogenous chemicals.