Differentiate between firm and industry. 

A firm is a business unit produced for the purpose of carrying out some kind of trading activity. The term "firm" is used in many ways, but the correct meaning is a business carried on under a trading style by partners. Many people use the term "firm" to embrace any business, i.e., Private Limited and Public Limited companies but this is technically incorrect. An industry is usually any grouping of businesses that share a common method of generating profits, such as the "movie industry", the "automobile industry", or the "cattle industry". It is also used specifically to refer to an area of economic production focused on manufacturing which includes large amounts of upfront capital investment before any profit can be realized, also known as "heavy industry."