RRB Group D GK Questions 2026

Vitamin A, chemically retinol, is needed to make rhodopsin, the light-sensitive pigment in the rod cells of the retina that lets us see in dim light.

Pellagra is caused by a lack of vitamin B3, also called niacin or nicotinic acid. The body can also make niacin from the amino acid tryptophan, so the disease is common where people live mainly on maize, which is poor in both.

Laughing gas is nitrous oxide, N2O, a colourless gas with a faintly sweet smell that makes people giggle and feel light-headed when they breathe it in.

The name itself gives the formula: 'hexa' means six, so sulphur hexafluoride has one sulphur atom joined to six fluorine atoms, SF6.

Real GDP measures the value of all final goods and services produced in a year at the prices of one fixed earlier year, called the base year, so that the effect of rising prices is removed and true growth can be seen.

In India the fiscal or financial year runs from 1 April to 31 March, so the year that starts on 1 April 2025 is written as 2025-26.

The Son rises at Amarkantak on the Maikal hills in Anuppur district of Madhya Pradesh, the same plateau from which the Narmada starts in the opposite direction.

The Kishanganga rises near Gurez in the Kashmir valley, flows north-west through Bandipora, crosses the Line of Control, where it is called the Neelum, and joins the Jhelum at Muzaffarabad in Pakistan-occupied Kashmir.

The Mahananda rises in the Darjeeling hills of West Bengal, near Kurseong, at a height of about 2,100 metres. It flows down through Siliguri, enters Bihar near Kishanganj, and then passes into Bangladesh, where it joins the Ganga (called the Padma there).

The Arabian Sea branch of the southwest monsoon strikes the Western Ghats first and drops most of its moisture on the windward western slopes, so the land on the eastern, leeward side gets little rain.

Nepal touches five Indian states: Uttarakhand, Uttar Pradesh, Bihar, West Bengal and Sikkim. Manipur lies far to the east in the North-East and shares its international border only with Myanmar.

Maharshi Karve, a social reformer from Maharashtra, founded India's first women's university at Pune in 1916, inspired by the Japan Women's University.

Annie Besant, an Irish-born theosophist, was the first woman to preside over the Indian National Congress, at its Calcutta session in 1917.

Zahir-ud-din Muhammad Babur founded the Mughal Empire in India after defeating Ibrahim Lodi in the First Battle of Panipat on 21 April 1526, and he ruled till his death in 1530.

Bindusara was the son of Chandragupta Maurya and became the second ruler of the Mauryan Empire in about 297 BCE, ruling till about 273 BCE.

On 21 April 1526 Babur defeated Ibrahim Lodi, the last Sultan of Delhi, at Panipat in present-day Haryana, and this victory ended the Delhi Sultanate and started Mughal rule in India.

A bill passed by both Houses of Parliament becomes an Act only when the President gives assent to it, as laid down in Article 111.

The Directive Principles of State Policy are placed in Part IV of the Constitution, from Article 36 to Article 51.

This Article gives the President the power to grant pardons, reprieves, respites or remissions of punishment, and to suspend, remit or commute a sentence.

These two Articles create the Council of Ministers that actually runs the Union government. Article 74 says there shall be a Council of Ministers headed by the Prime Minister to aid and advise the President, and the President acts on that advice.