Answer 1

The only pre-requisites to start learning ML are:

Basic Linear Algebra - Having a good knowledge of linear algebra would be very helpful.  For the beginning topics of ML like regression analysis, etc; knowing the basics of Linear Algebra would suffice. But as one goes on to more deeper in ML, a bit more knowledge of LA would be required.Programming Experience - Prior  programming experience would be very useful. People mostly program in Python, Java and R. But Python and R clearly stand out to be the leaders in the recent days.  Learning Python is very easy and shouldn't take more than two months to get through with the basics.