Final answer:
The correct answer to the question is 'A) survival functions - emotion'. The brain of primitive vertebrates mostly regulates survival functions, while the more complex mammalian brain allows for emotion and higher cognitive abilities.
Step-by-step explanation:
In primitive vertebrate animals, the brain primarily regulates survival functions; in lower mammals, the brain enables emotion. This is because many of the higher neurological functions, such as memory, emotion, and consciousness, are the result of cerebral function. The cerebrum in primitive vertebrates is quite basic, with the primary function connected to the sense of smell. However, in mammals, the cerebrum is highly developed and includes the cortex, deep nuclei, and the limbic system, which are involved in emotion, memory, and behavior.
The mammalian brain is more complex than that of other vertebrates, and it has a significant capacity for learning and memory. Structures such as the basal nuclei are important for cognitive processes and planning movements, while the basal forebrain is crucial for learning and memory. The limbic cortex is a part of the limbic system associated with emotional responses.
In conclusion, the correct answer to the question is 'A) survival functions - emotion'. The mammalian brain, with its complex structures like the cerebrum, limbic system, and associated regions, has evolved to control higher functions such as emotion and cognition compared to primitive vertebrates that primarily manage basic survival functions.