Final answer:
The completed sentence with appropriate biological terms describes that highly complex animals have intricate brain structures, with numerous neurons transferring signals across the cerebral hemispheres and various lobes sharing similar cortical constructions.
Step-by-step explanation:
The sentence completed with appropriate words would be: The most complex animals have the most brain structures. Billions of neurons in the brain's left and right hemispheres transfer signals to different parts of the cerebrum. The frontal and temporal lobes have different functions, but both are made of folds of cortex.