Acetylene is the only fuel gas suitable for gas welding because of its favourable flame characteristics of both high temperature and high propagation rates. Other fuel gases, such as propane, propylene or natural gas, produce insufficient heat input for welding but are used for cutting, torch brazing and soldering.

Answer: C) Oenologist Explanation: Oenology is the science and study of wine and winemaking. So person who is specialist in that is called as Oenologist.

Whereas oxygen, nitrogen, and argon are not examples of greenhouse gases.

At high temperatures, the tungsten filament gets hot and atoms in the filament vibrate more. The electrons in the current now collide more with the atoms & more energy is needed to push the current through the filament. Hence, the resistance of tungsten increases with temperature.

This colorless liquid has a characteristic sweet smell (similar to pear drops) and is used in glues, nail polish removers, and in the decaffeination process of tea and coffee. Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large scale for use as a solvent.