It is generally thought that animals have undergone four major physiological and anatomical innovations during their evolution. These are (in no particular order)
A.
development of tissues, photosynthesis, bilateral symmetry, multicellularity.
B.
development of the versatile forelimb, multicellularity, origin of patterns of embryonic development, development of tissues.
C.
multicellularity, bilateral symmetry, origin of patterns of embryonic development, development of tissues.
D.
bilateral symmetry, development of tissues, origin of the multichambered heart, origin of patterns of embryonic development.
E.
origin of patterns of embryonic development, development of the versatile forelimb, origin of the multichambered heart, multicellularity.
