When comparing the brains of rats raised in a rich environment requiring lots of learning and motor behavior with the brains of rats raised as "couch potatoes" (greenough, et al., 1990), the cerebellums of the more active rats?

The cerebellum of the more alert rats comprises more neuronal connections and dendrites.  

The cerebellum attains information from the spinal cord, sensory systems, and other parts of the brain and then monitors motor movement. The cerebellum coordinates voluntary movements, like balance, posture, speech, and coordination, leading to a smooth and balanced muscular activity.  

The cerebellum is an essential component of the brain and is mainly accountable for motor control. This involves equilibrium, muscle tone, and balance as it associates with motion. Subsequently, it appears that the cerebellum may also exhibit additional activities, like emotional and cognitive functions.  

the answer to your question is b

it's d - life cycles - apex