Questions

Both 2 and 3 are clearly the diadvantages of circular list

In chemistry, a metal is an element that readily forms positive ions (cations) and has metallic bonds. Metals are opaque, lustrous elements that are good conductors of heat and electricity. Most metals are malleable and ductile and are, in general, denser than the other elemental substances.

Examples of metals are aluminium, copper, iron, tin, gold, lead, silver, titanium, uranium, and zinc.

Here Se - Selenium is an element but is not a metal, S - Sulphur is not a metal and I - Iodine is also not a metal.

Hence, Zn - Zinc is the only metal in the given options.

An index is an optional structure associated with a table to have direct access to rows, which can be created to increase the performance of data retrieval. Index can be created on one or more columns of a table.

Adventure tourism : to convert the adventure into pleasure for the purpose of tourism business

Attraction : Anything/object/activity, which attracts tourists and attach with it.

Amenities : Extra facilities, service added with attraction, accessibility and accommodation to create tourism. It includes trust, friendship, hospitality, etc.

Back of the house : Staffs who are not directly involved in providing service. Guests rarely interact with them

Defence Research and Development Organisation (DRDO) has developed an unmanned, remotely operated tank which has three variants - surveillance, mine detection and reconnaissance in areas with nuclear and bio threats. It is called Muntra.