Scorpion, spider and cockroach have ventral solid central nervous system. All three belongs phylum-Arthopoda.–Spider belongs to class-Archnida–Scorpion belongs to class-Archnida– Cockroach belongs to class-Insecta.

Ascaris is a common parasite found in the large intestine of man. It is world wide in distribution. The number of worms may be 500 or more in a single host. Ascarisis characterised by presence of neither true coelom normetamerism.

pseudocoelomate is any invertebrate animal whose body cavity is a pseudocoel, a cavity between the gut and the outer body wall derived from a persistent blastocoel,rather than a true coelom. Pseudocoelomate animal include the Rotifera and Nematoda

Mollusca mostly oviparous and a few viviparous. The development may be direct or indirect with trochophore,velliger and glochidium.

Cockroach belongs to phylum-Arthropoda. It has 10 pairs of Spiracles (2 pairs on thorax and 8 pairs on abdomen)

Salamander does not undergo any annual migration as it occurs in Siberian crane, Arctic tern and Salmon mainly for the search of food or for breeding

Trypanosoma, Noctiluca, Monocystis & Giardia are unicellular protists i.e. unicellular eukaryotes.

Metameric segmentation means body is divided externally as well as internally. This characteristic is present in annelida (e.g.earthworm) and arthropoda (e.g.cockroach). Their body is divided externally and internally as well