When the particles present in the fluid are so small that they cross the pores of the filter sheet, so these particles are not separated by the filter method. When these mixtures are rotated quickly, massive particles sit down, and the light particles remain above. Thus Centrifugation is a technique used for the separation of particles from a solution according to their size, shape, the density of the medium and rotor speed.

The aerodynamic diameter of an irregular particle is signified as the diameter of the spherical particle with a density of 1000 kg/m3 and the same settling velocity as the irregular particle. It indicates the equivalent diameter of a sphere having the same volume as that of the Aerosol.

One can apply the aerodynamic diameter to particulate pollutants or to inhaled drugs to predict where in the respiratory tract such particles deposit. Pharmaceutical companies typically use aerodynamic diameter, not geometric diameter, to characterize particles in inhalable drugs.

• Aerosols are defined as a combination of the liquid or solid particles suspended in a gaseous or liquid environment.

• In the atmosphere, these particles are mainly located in the low layers of the atmosphere (< 1.5 km) since aerosol sources are located on the terrestrial surface.

• Although, certain aerosols can still be found in the stratosphere, especially volcanic aerosols, ejected into the high altitude layers.

• The origin of the atmospheric aerosols is either natural or the result of anthropogenic activities.

o Natural sources of aerosols comprise sea salt generated from breaking waves, mineral dust blown from the surface by wind, and volcanoes.

o Anthropogenic aerosols comprise sulfate, nitrate, and carbonaceous aerosols, and are mainly from fossil fuel combustion sources.

Effects of aerosols:

• They affect the atmospheric chemical composition.

• They can reduce the visibility.

• They have significant impacts on air quality and human health (e.g. aerosols can cause damage to the heart and lungs).

• They serve as nuclei for the cloud droplets or ice crystals in ice clouds.

Thugs were the hereditary assassins mostly in regions of North and Central India whose profession was to deceive people and murder, mutilation and robbed them. They used to travel in Gangs, disguised as merchants or pilgrims. A 'Thuggee and Dacoity Dept' was created by William Bentinck and William Henry Sleeman was made its superintendent. The 'Thugee and Dacoity Suppression Acts' were a series of legal acts passed from 1836 – 1848

 Special powers of the 10 Autonomous Councils are given in the Sixth Schedule areas of Assam, Meghalaya, Tripura and Mizoram.

The Former SC (Supreme Court) Judge Justice Pinaki Chandra Ghose has been appointed as the first Lokpal, a national anti-corruption ombudsman. This comes five years after the President had given assent to the Lokpal and Lokayuktas Act, 2013. He has been appointed by a committee consisting of Prime Minister Narendra Modi and Chief Justice of India Ranjan Gogoi and Lok Sabha Speaker Sumitra Mahajan on March 23 2019.

A Lokpal is an anti-corruption ombudsman who represents the public interest. The phenomenon of an ombudsman is borrowed from Sweden. The term "Lokpal" was originated by Dr. L.M.Singhvi in 1963. The phenomenon of a constitutional ombudsman was first proposed in the parliament by Law Minister Ashoke Kumar Sen in the early 1960s.

The Lokpal has jurisdiction over the central government to inquire into allegations of corruption against its public functionaries and for matters which are connected to corruption. The Lokpal is responsible for enquiring into the corruption charges at the national level while the Lokayukta performs the same function at the state level. Minimum age of the Lokpal (chairperson/member) on the date of assuming office as the Chairperson or the Member must not be less than 45 years.

Buland Darwaza, was built in 1575 A.D. at Fatehpur Sikri during the reign of Akbar to commemorate his victory over Mahmud Shah III, Sultan of Gujarat.

Buland Darwaza is a mammoth gate and is also known to be the highest gate in the world. It is one of the finest examples of Mughal architecture that combines the magnificence of red and also buff sandstone decorated by white and black marble. It is a 15-storied high gateway acting as the southern entrance of the city of Fatehpur Sikri. The approach to the gate consists of 42 steps.

Geographically Indus valley Civilization was spread from Jhelum river to Hindon river (tributary of Yamuna river). It encompasses rivers like Chenab, Ravi, Sutlej and Jhelum but not Ganga.

Alauddin Khalji assumed the titile of Sikander-E-Sani meaning Alexander the Second. He also imprinted it on his coins. He was an ambitious emperor who wanted to acquire more and more territory.

Koeppen recognised Five major climatic groups. 4 of them are based on temperature and one on precipitation.

● These groups are: A – Tropical, B - Dry Climates, C - Warm Temperate, D - Cold Snow Forest Climates, and E - Cold Climates.

● The climatic groups are further subdivided into types, designated by small letters, based on seasonality of precipitation and temperature characteristics. The seasons of dryness are indicated by the small letters: f – no dry season, m – monsoon season, w – winter dry season and s – summer dry season.

● Climate Group Cs represents the Mediterranean climate (characterised by dry, hot summer)

Thus, option A is correct.