Questions

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.

The four most common soil erosion prevention methods are vegetation, geotextiles, mulch, and retaining walls.

By planting grass in areas of concentrated water flow, farmers can prevent much of the soil erosion that results from runoff, as the grass stabilizes the soil while still providing an outlet for drainage.

Preventing soil erosion is critical in protecting your property and exposed soil, whether from wind, weather, running water, and even the after-effects of the forest fire.

Toddy

A magnifying glass is a convex lens that is used to produce a magnified image of an object. It is also called a hand lens in laboratory contexts.

In computing, ".bak" is a filename extension commonly used to signify a backup copy of a file.