List the advantage and disadvantage of: a. coral reefs b. cephalization c. coelom d. ecdysis e. multiple host life cycle f. proglottids g. multiple mouths h. incomplete digestive tract i. ventral nerves j. parthenogenesis k. statoblasts l. ontogenetic torsion m. hydrostatic skeleton

Explanation:

a ) Coral reefs :

Advantage: provides home to different fishes , can naturally break the water and minimize wave impact which helps us from cyclones and typhoons .

 Disadvantages:  can cause harmful damage to the ecosystem. Apart from natural reefs some people have started using artificial coral reefs to dump waste into waters .

b. Cephalization

Advantage: it means having a head which contains brain and primary sense organs in it and all neurons are concentrated in one region. With cephalization the development of brain do occur and the sense organs are located in head.

Disadvantages:  it is considered to have great importance in evolution the animal cannot see what's happening behind its head

d ) Ecdysis:

Advantage: It helps the organisms for longer growth .

Disadvantages: During the process the organisms were vulnerable till the exoskeleton hardens.

e ) Multiple host life cycle

Advantage: They can survive easily without facing competition.

Disadvantage: Sometimes they also become part of other food web and eaten up easily by others.

f) Proglottids

Advantage: It is a complete reproductive unit for tapeworms. So it helps in reproduction.

Disadvantage: There is no as such disadvantages as it helps the worms.

g ) Multiple mouths

Advantage: Helps in catching the prey.

Disadvantage: Very fast ingestion and engetion so sometimes it develops starvation like condition.

h  ) Incomplete digestive tract:

Advantage: Simple system having no complexity.

Disadvantage:Having only one opening for both ingestion and egestion which is very primitive type of digestion and makes it slow.

i ) Ventral Nerves

Advantage: It provides the body with better range of movement.

Disadvantage: It becomes more prone to damage.

j )  Parthenogenesis

Advantage: It helps in reproduction during scarcity thus help in boosting the Population as well as in genetic Stability

Disadvantage: It limits the genetic diversity that comes from repeatedly combining genetic material.

k )  Statoblasts  

Advantage: It can survive in harsh conditions such as freezing and desiccation.

Disadvantage: Sometimes it become prey for fishes.

l ) Ontogenetic torsion

Advantage: In aquatic organisms it is useful as the anterior positioning may be useful for preventing sediment getting into the mantle cavity while in terrestrial animals also ventilation is better with anterior positioning which is provided by this.

Disadvantage:The torsion may be results in harmful changes also.

m ) Hydrostatic skeleton -

Advantage: HEALING takes place quickly compared to organism with bone skeleton , grows back itself even after damage due to hydrostatic skeleton .

Disadvantage: there is no proper structure because the organisms don't have muscles.