The lion’s mane jellyfish can be up to 8 feet wide. In spite of its large size, it has no structures for bulk flow to deliver oxygen to its cells. How can it be so large, and lack a mechanism for bulk flow? A. The jellyfish is surrounded by water, so the concentration gradient between the water and the jellyfish is steep, making the rate of diffusion across tissues very high. B. The jellyfish is filled with tissue made of structural cells that are not metabolically active. Therefore a mechanism to transport oxygen to its interior is not necessary. C. The jellyfish body is actually a series of intricate folds, so the ratio of surface area to volume is maximized and diffusion occurs as it would across a tissue one or two cells thick. D. The jellyfish does not have receptors for sensing the environment, so does not need a mechanism for transmitting signal molecules throughout the body.