Diversity in Living Organisms

Ichthyophis and ureotyphus belong to order Apoda (limbless amphibians).

A poikilotherm is an organism whose internal temperature varies considerably. Both amphibians as well as reptiles are poikilothermal animals.

In chordates, central nervous system is dorsal, hollow and single. Heart is ventral in chordates.

Basis of classification of phylum Protozoa and Annelida are locomotary organs.

Non-nucleated RBCs are found in camels.

Mollusca – Circulatory system is open and lacunar type. Arthropoda – Circulatory system is open with dorsal heart.

In sponges, excretion takes place through general body cavity. 

Flatworms are bilaterally symmetrical, triploblastic and acoelomate animals with organ level of organization.

Out of the given characteristics, only 1 is correct for organisms belonging to Phylum Platyhelminthes. Bilaterally symmetrical, dorso-ventrally flattened and mostly un-segmented body is characteristic feature of organisms belonging to Phylum Platyhelminthes or phylum of flatworms.

This option is correct because Mycoplasma and Acholeplasma are the genera of Mollicutes that exhibit pleomorphic morphology.

Grey foam-nest tree frog minimises the chance of overheating by turning white.

Toads possess warty (bumpy) skin that helps the animal in blending more effectively into its environment, by breaking up its visual outline.

True toads possess Bidder's organ, which may have a role in reproduction.

Full neotany is seen in Ambystoma tigrinum (salamander). They become sexually mature in their larval form and retain lot of larval characteristics in the adult form.

The ability of some amphibians to change their colour by expansion and contraction of pigment cells is called metachrosis.