Answer: D) Monopolistic competition
Explanation: Monopolist competition is the competition in the marketing field by selling the products which are different from each other on basis of certain parameters such as brand.
According to the situation mentioned in the question ,presence of 12 airlines for opting are huge amount where airplane is viewed from product point of view and thus, it will create a imperfect competition.
Other options are incorrect because perfect competition is raised by the perfect market of products, monopoly is the situation with no competition and oligopoly is the competition with limited number of seller and their products.Thus, the correct option is option (D).
B. germany
Germany was the scapegoat for WW1
Homesteaders living on the great plains were what you call "Extremely Dramatic". There were lots of conditions on the great plains that affected settlers lives. Here are these problems; building houses, staying healthy, extreme weather, lack of fuel, Indian Attacks, lack of isolation, keeping clean, lack of water, and pests and vermin. The problem with the bugs were grasshoppers. Grasshoppers ruined their crops. Building houses from wood was expensive. The settlers couldn't afford building houses from wood, so they built it from sod. The walls and floors were infested with bugs and lice, because these homes were built from dirt and grass. It would leak in the homes when it rained. They also had problems staying healthy because of the insects. The insects that flew around would inject disease into their bodies. In other words, There are three things that helped them survive, and 3/3 of these examples issued technology. 1.) Barbed wire, 2.) steel plow, and 3.) windmills. The barbed wire was for housing reasons, the steel plow was for cutting through tough prairie sod, and the windmills for pumping water out of the ground. :)
Answers would be great if there was options