In Jainism, the concept of praan (life-forces or vitalities) is significant in understanding the nature of living beings (jivas) and their capacities. According to Jain philosophy, there are ten praanas:

1. Sparsh-indriya (touch)
2. Ras-indriya (taste)
3. Ghrana-indriya (smell)
4. Chakshu-indriya (sight)
5. Shravan-indriya (hearing)
6. Mano-bal (mind)
7. Vachan-bal (speech)
8. Kaya-bal (body or physical force)
9. Shwasoshwas (respiration)
10. Ayu (life-duration)

Jain texts do not specifically rank these praanas as "strongest" or "weakest"; rather, they describe the combination and presence of these praanas as determining the level of consciousness and capability of a living being. For example, a human being possesses all ten praanas, while a one-sensed being (like a plant) possesses only four.

However, in some interpretations, Ayu-prana (life-duration) is considered fundamental, because without life, none of the other praanas can function. But each prana has its unique importance and role.

So, in summary: Jainism does not explicitly state which praan is the "strongest." Each praan is essential for the functioning and classification of living beings. Ayu-prana (life-duration) is sometimes seen as fundamental, but no praan is described as "strongest" in the scriptures.