Answer: D) Japan Explanation: Maglev trains are used in Japan, South Korea and China only. Maglev derived from magnetic levitation using the principle of magnetic repulsion is a system of train transportation that uses two sets of magnets, one set to repel and push the train up off the track as in levitation then another set to move the 'floating train' ahead at great speed taking advantage of no friction. Maglev trains are therefore quieter and smoother than conventional trains, and have the potential for much higher speeds Despite over a century of research and development, maglev transport systems are in operation in just three countries Japan, South Korea and China.   Hence Maglev -- Magnetic-levitation.

Answer: B) Accoustics Explanation: Accoustics is a subject deals with the Study of sound   Aesthetics is a Philosophy of fine arts   The science or art of flight is called Aeronautics   The science of soil management is called Agronomy.

Answer: C) seating a child to small to hold on the operator in front of the operator Explanation: Two passengers behind the operator is safe for a PWC.

Answer: B) Coins Explanation: Numismatics is the study or collection of currency, including coins, tokens, paper money, and related objects.

Answer: C) Heterotroph Explanation: Producer are Autotrophs as they prepare their own food and does'nt depend on others as Customers or Heterotrophs which depend on producers or Autotrophs.

Answer: B) Nauru Explanation:

Answer: C) Petrology Explanation: The scientific study of rocks is called petrology, which is an essential component of geology.

Answer: A) Pila globosa - pearl Explanation: Pinctada vulgaris is a bivalve from which pearl is obtained.