Final answer:
The diffuser on a multi-place life raft helps with gas and nutrient exchange while preventing fluid diffusion into the interstitial space, thus maintaining a balance necessary for survival.
Step-by-step explanation:
The purpose of the diffuser on a multi place life raft is to assist with gas and nutrient exchange and to prevent the diffusion of fluid into the interstitial space. The diffuser helps to maintain the proper balance of gasses within the enclosed environment of the life raft, which is vital for sustaining life and preventing hypoxia among the occupants. Moreover, by preventing the undesired diffusion of fluid into the interstitial space, it helps sustain a stable environment that is conducive to survival in a marine setting.