Mac OS X El Capitan Vs. MacOS Serra

Mac OS X El Capitan is very similar to Mac OS Serra by the looks but the only thing different is MacOS Serra includes Siri (Who can be very annoying). El Capitan is well known and better than MacOS Serra because El Capitan can be run on older computers up to the 2007 MacBook Pro as to MacOS Serra can be running on Macs as old as the 2009 Macbook. The 07 Mac Book Pro can not run MacOS Serra. The number of operating systems from mac goes by numbers or names, for example El Capitan is 10.11 and MacOS Serra is 10.12. El Capitan and MacOS Serra is very similar but Serra includes Siri.