D. Asteroids vary greatly in size and are mostly made up stone, iron and nickel
Earth's orbit and climate change
Organ systems is the answer
Answer:
When an organism excretes or dies, nitrogen is in the form of organic nitrogen in its tissues (e.g. amino acids, DNA). During the ammonification process, many fungi and prokaryotes then break the tissue down and release inorganic Nitrogen into the atmosphere as ammonia.
Explanation:
Plants use their roots for nitrogen compounds. When they consume the seeds, animals acquire certain chemicals. When plants and livestock die, or animals excrete waste, the organic nitrogen compounds return to the soil, where microorganisms known as decomposers break down their compounds.
Answer:
TCR
Explanation:
Helper T cells are the CD4T cells that are present in the inactive form. These cells have receptors for antigens on their surface. These antigen receptors are called T-cell receptors (TCRs). The function of TCR is to recognize and bind to specific foreign antigen fragments that are presented in antigen–MHC complexes. Different helper T cells have their unique TCRs to recognize a specific antigen–MHC complex. The CD4 proteins of helper T cells also interact with the MHC antigens and help maintain the TCR–MHC coupling.
