Answer:
The correct answer is - Disruptive selection.
Explanation:
Disruptive selection is a mode of natural selection that exhibits that two extreme values of phenotypic traits of the population are favored by this population than the population with their intermediate values. Disruptive selection occurs when there is a fitness advantage of extreme values of phenotypic traits over more intermediate phenotypes.
In this case, the largest males mates more, due to fact that they can guard the females, than smaller males. The smallest fishes also get a high number of mates as are able to mate with the females quickly without coming to the notice of larger males.
Are you talking about a fruit fly?
Answer: Booster dose of vaccine is given to elicit a secondary immune response ( by means of re-exposure of pathogen in the booster dose) so that more number of long lived antibody producing plasma cells are produced in the body.
Due to this, a higher level of protection is created in the body.
Whenever the body encounters the disease causing agent, it can easily clear off the infection.
Thus, booster dose serves as an additional vaccine dose to boost the memory of the immune system against a particular disease.
Example of vaccine that require booster dose- HPV ( human pappiloma virus), Hepatits A, Hepatitis B, Polio.
