Final answer:
Cortical nephrons constitute approximately 85% of the nephrons in the human kidney, serving as the primary unit for filtering blood.
Step-by-step explanation:
The cortical nephrons make up approximately 85% of the nephrons in a human kidney. Nephrons are the functional units of the kidney that are involved in the process of filtering blood and generating urine. Each kidney contains over one million nephrons which consist of a renal corpuscle, a renal tubule, and the associated capillary network. There are two types of nephrons: cortical nephrons which are situated deep within the renal cortex, and juxtamedullary nephrons which are located close to the renal medulla. The former make up the majority of nephrons.