The answer is negative controls. These are groups where no phenomenon is probable. They ensure that there is no effect when there should be no effect. Where there are only two possible outcomes, e.g. positive or negative, if the treatment group and the negative control both produce a negative result, it can be concluded that the treatment had no effect. If the negative control group and the treatment group both yield a positive result, it can be inferred that a puzzling variable is involved in the occurrence under study, and the positive results are not only due to the treatment. In other examples, outcomes might be measured as lengths, times, percentages, and so forth.
Los aminoácidos químicamente son sustancias que estan formadas como su nombre lo indica, por un grupo amino y uno carboxilo, unidos ambos a un carbono central. Recordemos que el átomo de carbono tiene valencia 4, es decir, tiene cuatro lugares para sostener enlaces. Por lo tanto el resto los puede ocupar con átomos de hidrógeno u otras cadenas carbonadas a las que simbolizamos con la letra R. R puede ser un grupo metilo o un etilo o un gruo de más carbonos o también un anillo aromático, etc
Answer:
C.
Event A represents volcanic eruption and Event B represents creation of mountain ranges.
Sorry if it's wrong :(
