Processing the check is IRS's responsibility. If they accepted your check, but do not process it, it is their fault. Once they accept your check, your end of the deal has ended. A while back, I got a notice that I did not pay my state tax.
1 The xiphoid process (Latin: processes xiphoideus) is a small triangular cartilaginous extension of the breastbone.
Meiosis. Meiosis is the process by which sex cells (gametes) are made in the reproductive organs. It involves the division of a germline cell (diploid) into four genetically distinct haploid daughter cells.