Question

Cnidarians exhibit two types of body forms. What are they? How do they differ from each other? Give one example in each.

Answer 1

Hint: Cnidarians have a higher degree of dynamic organisation than Porifera. They have a non-cellular mesoglea between the outer and interior tissue layers. Cnidarians have a well-developed digestive system that enables them to perform extracellular digestion. Cnidocytes are specialised cells that transmit prey toxins and serve as a warning system against predators.

Complete answer:
Polypoid or medusoid are the two fundamental body forms of Cnidarians. The polypoid is a coral or anemone that has one side affixed to a substrate or connected to a colony of other creatures of the same species, and the opposite side is attached to a substrate or is part of a colony of other organisms of the same species. The organism is essentially upside-down in the Medusoid form, with the mouth and tentacles pointing downward.

POLYPOID	MEDUSOID
Polyps are sessile.	Medusae are mobile.
Possess a tubular shape.	Have a bell shaped body.
Polyps' mouths are angled upwards toward the water.	Medusa's lips are pointing downwards towards the water.
Manubrium is absent.	It is present.
Sense organs are absent in polyps.	Photoreceptors and statocyst are present in medusae.
Can reproduce sexually as well as asexually.	Exclusively sexual reproduction.

Note:
It's impossible to say how the various cnidarian groups are related. The bulk of hypotheses about the evolution of the phylum Cnidaria treat radial symmetry and tissue organisation as proof that the group is primitive.
Cnidaria is the first multicellular animal to display tissue level organisation in terms of evolution. Cnidaria are organisms that are diploblastic. Diploblastic organisms are made up of two layers of embryonic tissue. The two embryonic layers found in Cnidaria are ectoderm and mesoderm.
They have two layers of cells in their body walls: the outer epidermis and the inner gastrodermis, which are separated by a gelatinous layer termed the mesoglea. They are symmetrical in the radial direction. Coelenterata has both intracellular and extracellular digestion. A horny or calcareous exoskeleton or endoskeleton supports the body of several coelenterates.