Basic yoga terms on 1) is answered very differently in 4.3ff and 6.18-30. It may be that the latter is a continuation of the former or that it offers an alternative to it or even that 4.3ff is an interpolation. As Deussen points out, the core text is structured around three questions: 1. how does the atman enter the body? 2. Basic yoga terms 2016.
Basic yoga terms Yoga Poses 8.