1.1 Animals which are irregularly shaped summocal 1.2 Animals which can be cut in any vertical plane through their central
axes (plural of axis) to give mirror images zu
1.3 Animals that can be cut into mirror images in one plane only
1.4 Animals that remain attached to a substrate for most of their lives
1.5 Animals that swim weakly or drift in water
1.6 The accumulation of sense organs at one end that often leads to the
development of a head
1.7 The presence of a definite upper and lower surfaces in animals
1.8 Animals which arise from cells arranged in two germ layers
1.9 Animals in which all the tissues develop from three germ layers
1.10 The germ layer that gives rise to muscles and internal organs other
than those organs of the digestive tract
1.11 The germ layer that gives rise to the nervous system
1.12 The kind of skeleton that results from muscles working against
fluid in body cavities.
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