Most nitrogen fixation is performed by bacteria, but they are biotic, not abiotic. Lightning does have the ability to fix atmospheric nitrogen.
Cell-surface receptors are involved in most of the signaling in multicellular organisms. There are three general categories of cell-surface receptors: ion channel-linked receptors, G-protein-linked receptors, and enzyme-linked receptors.
Answer:
Respiration is a person's breathing and the movement of air into and out of the lungs.
Explanation:
The respiratory system provides oxygen to body tissues for cellular respiration, removes the waste product carbon dioxide.