Amphibians have a three-chambered heart and not four. All other options are correct.

 Elephantiasis refers to a parasitic infection that causes extreme swelling in arms and legs. This disease is caused by filarial worm.

There are many kinds of fish, some with skeletons made entirely of cartilage, such as sharks, and some with a skeleton made of both bone and cartilage, such as tuna or rohu.

Bryophytes are called the amphibians of the plant kingdom. The plant body is commonly differentiated to form stem and leaf-like structures.

Thallophytes, bryophytes and pteridophytes have naked embryos that are called spores.

Protochordates are bilaterally symmetrical, triploblastic and have a coelom.

Crocodile is the only reptile that has a four-chambered heart.

The plant body of Marsilea is differentiated into roots, stem and leaves and has specialised tissue for the conduction of water and other substances from one part of the plant body to another.

Angiosperms are called flowering plants. Ipomoea is an example of angiosperms.

Flatworms are acoelomates. There is no true internal body cavity or coelom in which well-developed organs can be accommodated. 

 Jointed legs are a characteristic feature of Arthropods. (the word ‘arthropod’ means ‘jointed legs’)

Plants that do not have well-differentiated body are called thallophytes. Examples are Spirogyra, Ulothrix, Cladophora and Chara.

Cycas is a gymnosperm. This term is derived from two Greek words: Gymno – meaning naked and Sperma – meaning seed. The plants of this group bear naked seeds and are usually perennial, evergreen and woody.

Cotyledons represent a bit of pre-designed plant in the seed. There can either be one cotyledon or two cotyledons.

Sycon belongs to Porifera, which have pores all over the body.