The jungle hills are a biome in the Overworld made up of a number of hills and mountains covered in jungle trees. They are pretty easy to identify, as the jungle trees themselves are unique in appearance and have vines hanging off them.
The Jungle Hills is a biome that is made up of lots of hills and mountains that are covered in oak leaves and jungle trees, but it does not have much wildlife. Since v1.18, the jungle hills biome is not considered a standalone biome and is not a part of the Jungle biome as a whole. This biome is a very wet biome since it receives a lot of precipitation causing a lot of rain. The biome itself is heavily populated with jungle trees which have long climbable vines hanging from the leaves. The vegetation found in the Jungle Hills biome consists of ferns, dandelions, poppies, vines, cocoa beans, and oak leaves as ground cover.
Since the jungle hills biomes are on high and mountainous terrain, a lot of passive mobs like wildlife don't spawn too often. Hostile mobs such as creepers, spiders, zombies, etc. can still spawn in the dark forest hills biomes.
Jungle hills are a variant of jungles that occur on hills and mountains. They don't have a lot of wildlife spawns but the monster spawn rates are unaffected. This biome is quite rare since jungle biomes are not commonly generated.
A. Since jungle biomes are not generated too often, jungle hills are quite rare.
A. Passive wildlife mobs such as sheep, cows, etc. are not found in jungle hills, but hostile mobs such as zombies, creepers, etc. spawn at their normal rates.