Which form of nitrogen can be used by plants and animals

Plants and animals primarily use nitrate (NO₃⁻) and ammonium (NH₄⁺) forms of nitrogen.

1. **Nitrate (NO₃⁻)**: This is the most common form of nitrogen taken up by plants. It is absorbed by plant roots and is then utilized in various metabolic processes, including the synthesis of amino acids, proteins, and nucleic acids.

2. **Ammonium (NH₄⁺)**: Plants can also take up ammonium, which can be directly absorbed by roots. Some plants prefer ammonium over nitrate, especially in acidic soils.

Animals acquire nitrogen primarily through the consumption of plant material or other animals that contain proteins, DNA, and other nitrogenous compounds. Once ingested, nitrogen is utilized to synthesize their own proteins and nucleic acids.