Complex sentence: M is comparatively small, only 170 verses, made up almost exclusively of teachings; it probably was not a single source, and while some some of it may have been written, most seems to have been oral.
Split into simpler sentences: M is comparatively small, only 170 verses, and is composed almost exclusively of teachings. It probably was not a single source, and while some some of it may have been written, most seems to have been oral.