Ans.1.
Cnidarians are lower eukaryotic organisms that include aquatic invertebrates, such as jelly fish, hydra and corals. These organisms show two types of body plan, medusa and polyp, both of which show radial symmetry.
Sponges belong to phylum Porifera that includes simpler asymmetric, marine organisms, with no body plan.
Thus, the correct answer is option). 'they have a medusa body form.'
Ans.2.
The corals are marine organisms that belong to phylum Coelenterata. Corals are often called as medicine chests of the sea as they are used for the treatment of various diseases, such as cancer, ulcers, and cardiovascular diseases.
Corals are easy to grow and provide a cost-effective way for collection, screening, and production of new medicines. So, there is an advantage of using corals to treat cancer and other disease as it is less expensive than drugs, which are synthetically produced in labs.
Thus, the correct answer is option). 'it is often less expensive to use than chemicals produced in a lab.'
Ans.3.
Both sponges and corals are used for the treatment of various diseases. For example, chemicals from bryozoans, such as bryostatin 1 are used for the cancer treatment in humans. Likewise, corals are also used for the treatment of cancer.
Thus, the correct answer is option). 'both are a source of chemicals that may be used to fight human diseases, such as cancer.'
Ans.4.
Most of the sponges do not release their eggs into the water, until they hatch. After fertilization, the zygote remains attached to the mother body and develops into larva, having cilia within its outer layer of cells. The cilia function in movement of larva and enable the larva to swim.
Thus, the correct answer is option). 'helping the larva swim out of the adult sponge.'
