There is a Hadith about the day of resurrection which states, that humans will be resurrected from the end part of their coccyx bone.
This Hadeeth is presented in Saheeh Al-Bukhaari and Saheeh Muslim on the authority of Abu Hurayrah may Allaah be pleased with him: The Prophet, said: "The whole (body) of the son of Aadam (Adam) will be consumed by the earth except for the tailbone, from which he was created and from which he will be created anew."
Another version of the Hadeeth was reported on the authority of Abu Sa'eed may Allaah be pleased with him: he asked: "What is it like, O Messenger of Allaah?” He said: "Like a grain of mustard." [Ahmad and Ibn Hibbaan] ...
Moreover, another Hadeeth reads: 'It is the first to be created and the last to decompose.' ...
That this tiny part of the coccyx bone which is usually mixed with dust and soil in the grave is rather intangible. According to the apparent indication of the Hadeeth and its versions, this tiny part of the human body, the tailbone, which is as small as a grain of mustard, does not decay at all.
(sunnah.com reference for the first hadith)
My question is: How is it possible?
What if the body was cremated? That extreme heat will kill any living organism.
I really need an answer this has been bothering me for some time. The first part of the hadith is correct where it says that the coccyx bone is where creation starts, but the decaying is what is bothering me.