Final answer:
Human erythrocytes are widely studied because they are abundant in the blood, lack a nucleus which allows more room for oxygen-carrying hemoglobin, and their shape maximizes gas exchange efficiency.
Step-by-step explanation:
Human erythrocytes are popular to study because they are the most numerous cells in the blood and are crucial for oxygen transport. A microliter of human blood contains between 4.2 and 6.1 million red blood cells, which also account for about 25 percent of all cells in our body. The cells' biconcave shape optimizes the surface area to volume ratio, beneficial for gas exchange, and their lack of a nucleus provides more room for hemoglobin, the iron-containing protein that binds oxygen and carbon dioxide. This makes them ideal for studying cellular processes related to oxygen transport and the physical characteristics that allow efficient gas exchange.