Which of the following observations to explain the conformational changes that occur in hemoglobin upon binding to oxygen? a. the four heme groups are positioned close to the surface of the molecule. b. both the heme and the iron ion in the deoxy conformation are in a planar conformation. c. an αβ dimer rotates and slides with respect to the other dimer upon binding oxygen. d. all of the above

parasites can detrimentally affect their host, but also must not allow their host to die before they can complete their life cycle. some parasites have complex life cycles with many different hosts, and have had to find ways of persisting in many different environments during the change from one host to another. ectoparasites live outside the body of the host, and can more easily  disperse, but are  more exposed to predators, parasites, parasitoids. endoparasites live inside the body of the host, and are therefore protected from the outside environment. but they can be  attacked by the host's immune system. they have therefore developed  mechanisms for dispersal such as  complex life cycles.

allowed for the prediction of the properties of missing elements.