Context: The motor centers of reptiles react to sensory cues of vision, sound, touch, chemical, gravity, and motion with pre-set body movements and programmed postures. With the arrival of night-active mammals, smell replaced vision as the dominant sense, and a different way of responding arose from the olfactory sense, which is proposed to have developed into mammalian emotion and emotional memory. The mammalian brain invested heavily in olfaction to succeed at night as reptiles slept—one explanation for why olfactory lobes in mammalian brains are proportionally larger than in the reptiles. These odor pathways gradually formed the neural blueprint for what was later to become our limbic brain.

Question: What parts of reptiles respond to sensory cues?
Answer: motor centers

Question: What is the principal sense of night-active mammals?
Answer: smell

Question: Why were early mammals active at night?
Answer: reptiles slept

Question: What developed from the mammalian odor pathways?
Answer: limbic brain

Question: How do the olfactory lobes of mammals compare in size to those of reptiles?
Answer: larger

Question: What parts of reptiles don't respond to sensory cues?
Answer: Unanswerable

Question:  What is the principal sense of morning-active mammals?
Answer: Unanswerable

Question:  Why were early mammals active in the morning?
Answer: Unanswerable

Question:  What developed from the mammalian sonic pathways?
Answer: Unanswerable

Question: How do the olfactory lobes of mammals not compare in size to those of reptiles?
Answer: Unanswerable