mANDUkya Upanishad
(Gaudapada kArikA not included)
The muNDaka Upanishad, towards its conclusion, refers to the fifteen constituents of the human body, each of which resolves into its respective source at the time of liberation:
गताः कलाः पञ्चदश प्रतिष्ठा देवाश्च सर्वे प्रतिदेवतासु ।
कर्माणि विज्ञानमयश्च आत्मा परेऽव्यये सर्व एकीभवन्ति ॥ — 3.2.7, muNDaka Upanishad.
Meaning: To their sources repair the fifteen constituents (of the body) and to their respective Gods, go all the gods (of the senses). And the karmas, and the self that simulates the intellect, all become unified with the Supreme Undecaying. [Translation: Swami Gambhirananda.]
However, the prashna Upanishad, which precedes the muNDaka, speaks in its final question of sixteen parts constituting the individual. There thus appears to be a discrepancy between the two Upanishads regarding the total number of constituents. Shankara too does not explicitly explain the reason for this difference.