The answer is; B
As air cools, its capacity to hold moisture reduces. This is is why as warm humid air cools, it reaches a saturation point, and the water moisture begins to form droplets. These droplets form clouds in the atmosphere.
Answer:
Helper T cells are arguably the most important cells in adaptive immunity, as they are required for almost all adaptive immune responses. They not only help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells.
Explanation:
Helper T cells become activated when they are presented with peptide antigens by MHC class II molecules, which are expressed on the surface of antigen-presenting cells (APCs). Once activated, they divide rapidly and secrete cytokines that regulate or assist the immune response.
ATP or Adenosine triphosphate is well know for it's energy source but despite it has many roles in cell. ATP is primarily used as energy source as it has higher energy in it's phospho-di-ester bonds between P and P atoms. It is hydrolyzed to ADP & AMP to give energy.