<prompt> The type of sampling where the individual himself introduces the other subjects of surgery is called as:Systemic samplingSnowball samplingIntroductory samplingSuccessive sampling  <response>: Snowball sampling is a technique for developing a research sample, where existing study subjects recruit future subjects from among their acquaintances.It is a type of non-probability sampling.This sampling technique is often used in hidden populations which are difficult for researchers to access; example, drug users or commercial sex workers.Thus, the sample group appears to grow like a rolling snowball.Because sample members are not selected from a sampling frame, snowball samples are subjected to numerous biases. 