A. Mass extinction is the answer
Answer:
Kettlewell thought that if natural selection caused the change in the moth population, the following must be true: Heavily polluted forests will have mostly dark peppered moths. Clean forests will have mostly light peppered moths. Dark moths resting on light trees are more likely than light moths to be eaten by birds.
The student who caught the cold caused by this specific Rhinovirus was exposed to the exact same Rhinovirus 18 months later. Memory B cells of the immune system will protect her from getting the same cold again.
In immunology, a memory B cell (MBC) is a type of B lymphocyte that forms part of the adaptive immune system. These cells develop within germinal centres of the secondary lymphoid organs.
Memory B cells circulate in the blood stream in a quiescent state, sometimes for decades. Their function is to memorize the characteristics of the antigen that activated their parent B cell during initial infection such that if the memory B cell later encounters the same antigen, it triggers an accelerated and robust secondary immune response.
Memory B cells have B cell receptors (BCRs) on their cell membrane, identical to the one on their parent cell, that allow them to recognize antigen and mount a specific antibody response.
Learn more about memory B cell here : brainly.com/question/23423029
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The answer to the fill in the blank is option B) Authentication
Passwords, tokens, and fingerprint scans are all examples of Authentication.
We use passwords, tokens and even fingerprints since they can be unique identifications and are usually seen as more secure.
In the above options, fingerprints are seen as the most secure form of authentication since everyone has unique fingerprints.
One of the earliest forms of authentication were time cards used as early as the 1950s and even unique keys and stamps used by early civilizations.
