Researcher A measures study habits by recording the types of courses that students study for the most; Researcher B measures study habits as the time in minutes spent studying per week. Researcher A measured study habits as a variable; Researcher B measured study habits as a variable.

Qualitative, quantitative variables

Explanation:

There are many types of variables. Qualitative and quantitative variables are two variables in this.  

Qualitative variables :

These are the variables they are responsible for the values of names and labels. for example the color of the ball, the speed of a car, the breed of a dog. These are also called categorical variables.

Quantitative variables:  

These are the numeric variables. This variable counts the numbers. These are responsible for the measurement of quantity.  

answer; ///i believe the correct answer is (b) the writing of the ancients who lived in india after the indus valley inhabitants died out;