Include note about built-in datasets in R

[maneesha]

The list subsetting exercise references the built-in dataset mtcars. Consider including an explanation of what that is and why we did not need to define it as we did all our other datasets.

[Yatish0833]

I agree. Built-in R datasets should be introduced. The ability for students to see all datasets available to then using "data()" function is important. Maybe a good place to introduce would be at the very start of data structures lesson before building the feline-data.csv.

[naupaka]

Good suggestion!