Answer:
G-protein-linked receptor
Explanation:
Epinephrine acts via G-protein-linked receptors. The heterotrimeric G proteins located within the cell are activated by G protein-coupled receptors that span the cell membrane. Signaling molecules bind to a domain on the GPCR located outside the cell, and an intracellular GPCR domain then in turn activates a particular G protein.
Biotic Factors are any living components that affect other organisms, and since soil is not alive (soil is an abiotic factor) then you can eliminate A., B., and C. D is the answer choice that has only biotic examples.
Nervous tissue is made up of neurons and supportive cells. Throughout the human body the neurons carry electrical and chemical signals, while nutrition is provided by the supportive cells.
