Having the prothrombin mutation increases the risk of developing a DVT (a blood clot in the deep veins, typically the legs) and/or PE (blood clot that travels to the lungs). DVTs are dangerous because they can damage the veins, leading to pain and swelling, and sometimes to disability.
Checksum is the general term. CRC is one kind of checksum. An FCS is. a checksum (typically a CRC) appended to a frame during serial data. transmission, so an FCS is one use of a praticular type of checksum. Some are better than others in detecting specific kinds of errors. Some are more easily computed in software or hardware.
For the most part they are extremely similar. The main difference is that CA has a separate Pregnancy Disability Leave. CFRA does not run concurrently with PDL, but FMLA typically will. As a result, a new mother may have CFRA time remaining after the FMLA time has run out.