What type of developmental constraint has prevented animals from evolving body parts that are moving wheels into which blood circulates?

MCQs on the field of developmental biology from its origins to the present day, from seminal historical experiments to modern techniques and the mechanisms of development. Covers a variety of organisms from their start at fertilization through the stages of their development and on to entire organismal and post-embryonic development, as well as the molecular and genetic regulations involved in these processes.