Question

red blood cells are able to transport oxygen because of their __ and because they contain __, which is a protein that binds to oxygen molecules. concave shape; hemoglobin concave shape; myoglobin hematin spherical shape; myoglobin hemerythrin hemocyanin biconcave shape; myoglobin spherical shape; hemoglobin biconcave shape; hemoglobin

Explanation:

Red blood cells have a biconcave shape. This shape increases the surface - area - to - volume ratio, which is beneficial for gas exchange (including oxygen transport). Hemoglobin is the protein in red blood cells that specifically binds to oxygen molecules. Myoglobin is mainly found in muscle cells and has a different function (stores oxygen in muscle). Hematin is a breakdown product of hemoglobin. Hemerythrin and hemocyanin are oxygen - carrying proteins in some invertebrates (not in human red blood cells). Spherical shape is not the characteristic shape of red blood cells for efficient oxygen transport.

Answer:

biconcave shape; hemoglobin