How do leguminous plants contribute to the nitrogen cycle?*1 pointThey absorb nitrogen compounds from the atmosphere.They facilitate denitrification in the soil.They fix nitrogen gas into ammonia.They release nitrates into the soil.

Leguminous plants contribute to the nitrogen cycle primarily through a process called nitrogen fixation. Here's how it works:

1. Nitrogen Fixation: Leguminous plants have a symbiotic relationship with bacteria known as Rhizobium, which live in nodules on the roots of the plants. These bacteria are capable of converting nitrogen gas from the atmosphere into a form that is usable by the plant - ammonia. This process is known as nitrogen fixation.

2. Absorption of Nitrogen Compounds: Once the nitrogen gas has been converted into ammonia, the plant can absorb and use it to make proteins and other organic compounds.

3. Release of Nitrates into the Soil: When the plant dies and decomposes, the nitrogen compounds it contains are released back into the soil in the form of nitrates. These nitrates can then be used by other plants, thus continuing the nitrogen cycle.

4. Denitrification: While leguminous plants do not directly facilitate denitrification, the nitrates they release into the soil can be converted back into nitrogen gas by certain types of bacteria. This process, known as denitrification, also plays a key role in the nitrogen cycle.