I am pretty sure the answer is D (combination)
The 3 main regions of the brain are the cerebrum, cerebellum, brainstem.
The answer is pheromones. Hope that helps :)
Bio tic Factors. An ecosystem is a community of organisms that interact with each other and with the and biotic factors in their environment. Abiotic factors are chemical and physical factors such as temperature, soil composition, and climate, along with the amount of sunlight, salinity, and pH.
i hope this helps you out if that didnt helpo you im very sorry i tried my best
have a great afternoon
FaithRawlins14