What is social stratification?
a) the change in a social rank of a person from one situation to another
b) the movement of an individual from one social class to another a change in status without any change in a person's social class
c) the process of placing individuals into groups, social classes, or ranks

The correct answer is C.

Explanation:

Social stratification is a process whereby members of a particular society are categorized into ranks as a result of some contributing factors like, race, wealth, education, power, gender, occupation and income. It is also an hierarchical placement of the members of a society based on their social status.

Social stratification is used in understanding the inequality in a society and  can also be based on economy and politics.

question - in 1827, john walker, a druggist in a small english town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. the druggist had discovered the first friction-chemical match, the kind we use to-day. it is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. although walker's match did not require the bottle of acid, nevertheless it was not a good one. it could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. in a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. the match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. it would ignite when rubbed on any dry surface, and there was no longer any sputtering. this was the phosphorus match, the match with which we are so familiar. according the paragraph what was the benefit of the new phosphorus match? it burst into flame when rubbed on sandpaper. it was made by mixing chemicals. it could be ignited on any dry surface. it threw fire in all directions.

answer - matches required natural chemicals