Microsoft Visual C++ 201X Redistributable Package

[#1]

What does this software do and what other programs need it. ?
My PC has about 6 versions of it going back to 2008 ?
Why doesnt MS just update and remove the old versions.
Can I safely delete the old versions?
I only have MS, Adobe and a few other programs installed in this Win 10 machine

[#2]

This is the C library runtime used used by various applications. When a native C / C++ application is compiled it's code is linked against a specific set of libraries, so in order for the functions call to work some vendors provide this runtime during the install process. So if you have older software for example it may use the 2005 runtime so to continue to use you need it installed.
In theory there is no reason why you can't unistall some of these but I suspect they are on your machine for a reason (i.e. they are needed). If I were you I would tend to leave them.