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.
7. Large Intestine and chemical digestion
8.stomach
9.capillaries
4.neurons
hopefully this is correct
Salt (not table salt!) is formed when an acid reacts with a base. Salt is a compound. Water is also produced as a by-product of this reaction.