From a quick Google search, IVIG infusions are a treatment used in the NHS, so yes if a consultant started you on that treatment you would have it for life if necessary and it would cost you nothing.

It doesn’t, the array is still in the same order it started in, it’s members are just printed to the console in numerical order.

It just prints the number 1 after 1 ms, 2 after 2 ms, 3 after 3 ms etc.

BMI is your weight divided by the square of your height

If you live somewhere with consumer rights, by law you can return it no questions asked within 14 days of receipt (actual length of time may vary, UK is 14 days)