Answer:
Aquatic.
Step-by-step explanation:
The temperature regulation is related to presence of water in a particular biome.
a) Temperate forest: This is a biome with a moderate in the moderate climates and is in between the regions of tropics and boreal.
b) grassland : This mainly have long grasses, flowers and herbs.
c) rainforest: They have extreme temperature conditions of high and low due to presence of tress and not water only.
d) aquatic : this biome has water so it will have most stable temperature.