1.
Lobe finned fishes are noted for the important feature of the lobe in their fins. Their fins contain many bones and muscles and hence they have a central appendage in their fins. The fins are very flexible and these support them when they are in land. Tetrapodes seem to have evolved form these lobe finned fishes.
The coelacanth, Latimeria chalumnae (infraclass Coelacanthimorpha) is one of the most famous fossil which is supposed to remain unchanged for more than 200 million years.
2)
Methane Hydrates are largely found beneath Arctic Premafast, Antartic ice and along continental margin as sedimentary deposits. Under sea when low temperature and high pressure persist methane is produced from organic matter which mixes with warm water in sufficient depth to evolve as Methane Hydrate. These are formed by precipitation or crystallization of methane migrating from deep water under geological faults. These block the ships also sometimes. The ice-core methane is a primary...