Questions

Numismatist: someone who studies or collects coins, paper money, or medals.

Philatelist: a person who collects stamps.

Ornithologist: a person who studies on birds.

Statistician: an expert in the preparation and analysis of statistics.

The distance in pitch between any two tones is called an interval.

Two sub groups of Himalayan Rivers are Trans Himalayan Rivers and Himalayan Rivers.

• Trans Himalayan Rivers :

These rivers originate beyond the Himalayas. They are The Indus, The Sutlej and The Brahmaputra Rivers.

• Himalayan Rivers :

These are the rivers originate from Himalayas. They are The Ganga, The Yamuna and their tributaries.

Communication by touch is called Haptics communication and the study of this is called as Haptics.

Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of Earth.

Statement 2 is also correct. But it is not the correct explanation for the 1st statement.

A sinkhole (in Karst topography) is a hole in the ground that forms when water dissolves surface rock. Often, this surface rock is limestone, which is easily eroded, or worn away, by the movement of water.

Formation of a Sinkhole: In a landscape where limestone sits underneath the soil, water from rainfall collects in cracks in the stone. These cracks are called joints. Slowly, as the limestone dissolves and is carried away, the joints widen until the ground above them becomes unstable and collapses. The collapse often happens very suddenly and without very much warning. Water collects in these collapsed sections, forming sinkholes.

Sinkholes also form when the roofs of caves collapse. Sinkholes are often funnel-shaped, with the wide end open at the surface and the narrow end at the bottom of the pool.Sinkholes vary from shallow holes about 1 meter (3 feet) deep, to pits more than 50 meters (165 feet) deep.