Answer: Mountain hills and terais depends on each other because mountains stand tall above the terai while the terai is the land below the mountain which can also be called a valley.
Explanation:Terai is a low land region containing some hill ranges. Looking out for its coverage, it covers 17% of the total area of Nepal. The Terai (also spelled Tarai) region begins at the Indian border and includes the southernmost part of the flat, intensively farmed Gangetic Plain called the Outer Terai. Mountain hills or Hilly is a mountain region which does not generally contain snow. It is situated south of the Himal. This region begins at the Mahabharat Range (lit. Great Indian, trad. the Lesser Himalaya) where a fault system called the Main Boundary Thrust creates an escarpment 1,000 to 1,500 metres (3,000 to 5,000 ft) high, to a crest between 1,500 and 2,700 metres (5,000 and 9,000 ft). It covers 68% of the total area of Nepal.