.An experiment involves 16 participants. From these, a group of 4 participants is to be tested under a special condition. How many groups of 4 participants can be chosen, assuming that the order in which the participants are chosen is irrelevant?

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.