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.
Skin pigments actually protect us from ultraviolet rays!
These limbs (see attached image) provide evidence of common ancestry because
they have the same basic structure. In evolution we have convergent evolution and divergent evolution; In convergent evolution we focus on the analogous structure; which have different ancestry but perform similar functions while in divergent evolution, we have homologous structures which have a common ancestry and similar structure; but performs different functions, like the limbs described above.
Answer:
Solubility is defined as the capability of the solute to dissolve in the solvent. Solubility depends upon the temperature. In the given graph, solubility of many salts is increases with increase in temperature but solubility of sodium chloride is relatively constant i.e. slightly effect of temperature.
In aqueous solution, sodium chloride completely exist as and ions. Thus, there is no external force required for its dissociation.
Hence, sodium chloride shows the least increase in solubility with increase in temperature.
Option (B) is correct answer.