Answer:
I think B is the correct answer
A pure substance is something that occurs in nature. An element is made up of one type of atom only and cannot be split further.
In simpler terms it is true an element is a substance that is made of ONE type of atom
In cross sectional research, a researcher compares multiple segments of the population at the same time.
<h3>What is cross sectional research?</h3>
It is a type of research design in which data are collected from many different individuals or segments.
This data are analyzed at one specific point and time.
Therefore, a cross sectional researcher compares multiple segments of the population at the same time.
For more information on cross sectional research kindly check
brainly.com/question/10879218
Answer: Social class
Explanation: Social class is the use of socio-economic status to rank individuals in a society. Social class ranks people on the social ladder of the society.
