Which among the following is exclusively marine? (a) Porifera (b) Echinodermata (c) Mollusca (d) Pisces

Ans. C-  Echinodermata.

Gas bladder or air bladder is a gas filled sac present in fishes. It helps in maintaining buoyancy. Thus, it helps fishes to ascend or descend and stay in the...

(a) Arthropoda 

(a) Spongilla

(a) tube feet 

(b) Coelenterata 

(a) Echinodermata

Pure tungsten has a high resistivity and a high melting point (nearly 3000oC). When an electric current is passed through the filament, the electric energy is converted to heat and...

b. the following is a marine fish Hilsa.