Answer 1

"Turtle graphics is a popular way for introducing programming to kids...The turtle module provides turtle graphics primitives, in both object-oriented and procedure-oriented ways. Because it uses tkinter for the underlying graphics, it needs a version of Python installed with Tk support."
- courtesy of turtle documentation

Answer 2

Sadly, no you cannot on SoloLearn You still can embed turtle into HTML. Use my code as an example:
https://code.sololearn.com/WagHqG2Pgm9S/?ref=app
https://code.sololearn.com/WvQtxMqvgk1q/?ref=app
https://code.sololearn.com/W49MLySi1Wth/?ref=app
https://code.sololearn.com/WX1HAjN2kCbk/?ref=app