During the third trimester, what happens to the cerebrum?

During the third trimester, what happens to the cerebrum?

• A. Cerebrum separates left and right
• B. Cerebrum fuses
• C. Cerebrum develops into brainstem
• D. Cerebrum weight decreases

Answer: (A)

In the third trimester, the cerebrum is clearly divided into two distinct hemispheres—the left and the right—with a deep interhemispheric fissure between them. This separation allows the hemispheres to specialize functions while remaining connected by the corpus callosum for coordination. The other ideas don’t fit: fusing would negate the distinct left-right structure; the cerebrum doesn’t transform into the brainstem; and the brain is actually growing, not losing weight, during late gestation.

In the third trimester, the cerebrum is clearly divided into two distinct hemispheres—the left and the right—with a deep interhemispheric fissure between them. This separation allows the hemispheres to specialize functions while remaining connected by the corpus callosum for coordination. The other ideas don’t fit: fusing would negate the distinct left-right structure; the cerebrum doesn’t transform into the brainstem; and the brain is actually growing, not losing weight, during late gestation.