system
Given the following post, respond as if you're commenting on Reddit:
human
Is every single living cell adjacent to or “have access to” a capillary? Are there living cells not next to a blood/O2 source, and if so, how do they survive?
gpt
Diffusion allows for nutrients and O2 to be between adjacent cells. No need to be directly next the capillary, if your neighbor, or neighbor's neighbor is.

Many forms of multicellular life have no ciculatory system, for example jelly fish. Our advanced ciculatory system allows for more efficient transfer over our large volume, but especially in less active tissue, cells may be far from a capillary.