Answer:
Herd immunity
Explanation:
Herd immunity refers to the resistance of a group of people against infection and the spread of a pathogen. It occurs when a high proportion of the members of that group are resistant against a particular pathogenic infection. When an earlier exposure or vaccination of a large proportion of individuals of a population does not allow the pathogen to spread among and infect the otherwise susceptible members of the population, the population is said to have acquired the herd immunity.
In the given example, vaccination of a large percentage of a population protected the susceptible individuals against a particular microbe. This represents an example of herd immunity.
C. Makes the most sense to me
In bird, females are heterogametic, produce two type of gametes. The two different sex chromosomes of a female bird has been designated to be the Z and W chromosomes. Whereas males have a pair of Z- sex chromosomes. Males are homogametic produce only one type of gametes with Z-sex chromosomes. Thus sex determination is ZW-ZZ type. In humans sex determination is XX-XY type. Males are heterogametic produce X and Y gametes and females are homogametic produce one type of gametes. Therefore, in bird sex are determined by female gametes.
