Answer:
They were poor, had lowpaying jobs like yard workers and servants, usually dropped out of school to help their families, and had small homes with typically lots of siblings
Because it is important to know the composition of the object
Density is the ratio of the mass of a sample to the volume occupied by that mass, and expresses how much mass there is per unit volume of a given portion of matter. Density is a physical property of extreme importance in the characterization, identification and use of substances or materials.
The answer is D
Hope this helps :D