B-lymphocytes are categorized as part of the adaptive branch of the immune system for all of the following reason but one. which of the following is not one of the reasons b-lymphocytes are considered part of the adaptive immunity? a) their receptors will bind to only one antigen. b) they are a first line of defense that can begin killing pathogens immediately. c) they require costimulation from an activated t- cell. d) they produce memory cells when activated.

B. They are a first line of defense that can begin killing pathogens immediately.

Explanation:

B-lymphocytes are not the first line of defense. On the contrary, innate immune cells such as basophils, dendritic cells, eosinophils, Langerhans cells, mast cells are the body's first line of defence.

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i guess you forgot putting it.

answer:

sequence 1- deletion

                  2- duplication

                  3- insertion

                  4- substitute

                  5- inversion