How are red blood cells able to move through narrow vessels to carry oxygen throughout a multicellular organism? (1 point) Responses They are small because they lack a nucleus. They are small because they lack a nucleus. They are long and thin with a tail-like end. They are long and thin with a tail-like end. They are flexible because they lack a plasma membrane. They are flexible because they lack a plasma membrane. They are small because their organelles are smaller than those of other cells. They are small because their organelles are smaller than those of other cells.

Answer 1

The correct response is: They are small because they lack a nucleus.

Red blood cells (erythrocytes) are unique in that they do not have a nucleus, which allows them to have a biconcave shape. This shape, combined with their flexibility, enables them to squeeze through narrow capillaries efficiently while maximizing the surface area for oxygen transport.