What is the main difference between structured and unstructured data?

answer is 4.

Explanation:

for an instance let's say you've got to make list of students who would stay after school for sports.then you have to collect data such as Student name _gender _the sport he or she will attend to. Then you get three columns of table to do that when you write those you can get a clear information seeing those data..

answer; i do believe its (d) modem;

they really not common the os x is just a better version of the os like in iphone theirs xr and their xs