Th memory cells differ from the effector cells in that the memory cells live longer. Two types of cells are produced by the clonal selection, these are the effector cells and the memory cells. Effector cells are relatively short lived activated cells that defend the body in an immune response. Effector B cells are called plasma cells and secrete antibodies, and activated T cells include cytotoxic T cells and helper T cells, which carry out cell-mediated responses. The production of effector cells in response first time exposure to an antigen is called the primary immune response. The memory produced at this time and only become active in case of a re-exposure to the same antigen that stimulated their formation.
The answer to this is A- Repeat the preceding music.
This sign is usually shown when you need to sing or play the same lines in a song and don't want to waste paper
A commensalistic relationship is one sides but neutral for the other party. Barnacles live on whales but whales are not directly affected by them. I do not believe the barnacle population decrease would affect whales at all.
Both need water to survive.
