In this interaction of guṇas, various things evolve within Prakṛti in response to Spirit (Puruṣa). The entire physical universe emanates from Prakṛti.
The first thing that evolves is intellect (mahad), which in turn gives rise to individuality (ahaṅkar).
From individuality arise the five sensory organs, and also the five “motor organs” (speech, touch, walking, evacuation, reproduction).