のせかい

…'s world; the world of …

→ の

phrase Common #3,866

…'s world; the world of … の links the preceding noun to せかい (世界, “world”), referring to the world or realm associated with that noun.

JA: 昆虫のせかいでは、常に力が優先する。

EN: In the world of insects, strength always takes priority.