Answer:
B. the appearance of lichens and mosses in an area where a glacier has recently melted away
Explanation:
Ecological succession, which refers to the series of changes that occurs over time in an ecosystem, can be of two types namely: primary succession and secondary succession.
Primary succession is a succession that involves an area where no form of life has grown previously, hence, the area of land is barren e.g bare rock. Primary succession is first colonized by species called PIONEER SPECIES e.g. lichens, mosses etc.
According to this question, "the appearance of lichens and mosses (pioneer species) in an area where a glacier has recently melted away" is an example of PRIMARY SUCCESSION.
Because you could easily contaminate the results of the urine if you don't follow exactly what the strict rules dictate This could be a very dangerous thing because if you contaminate the results, then other doctors would think that the patient has some disease that needs to be taken care of which in reality they do not. The patient could also have to go through things or waste money on things that they don't need to because there was something in the urine that wasn't supposed to be there which was added because they didn't follow the strict rules. Then the doctor who contaminated it could be sued for malpractice which is never a good thing.
Parasitism and autotrophism