Railway GK Questions 2026

The thyroid gland needs iodine to make the hormones thyroxine and triiodothyronine, and when the supply is short the gland enlarges in an attempt to trap more of it, which appears as a swelling in the neck.

Rabies is caused by a virus present in the saliva of an infected animal, usually a dog, and it travels along the nerves to the brain, where it causes inflammation, fear of water and almost certain death once the symptoms begin; it is prevented by vaccination after the bite, a…

Kala-azar, also called visceral leishmaniasis, is caused by the protozoan Leishmania donovani and is passed on by the bite of the female sandfly, which breeds in cracks of mud walls and damp soil.

Filariasis is caused by the thread-like nematode Wuchereria bancrofti, which is carried by the Culex mosquito.

Vitamin A is used to make rhodopsin, the pigment of the rod cells of the retina that allows sight in dim light, so a shortage of it makes a person unable to see properly at dusk or in a dark room.

Vitamin C, or ascorbic acid, is needed to make collagen, the protein that holds tissues together, so its absence weakens the gums and blood vessels and delays the healing of wounds.

This mosquito, marked by white stripes on a dark body, bites during the day and breeds in clean stored water in coolers, tyres and flower pots, which is why dengue control campaigns concentrate on emptying household containers.

Four species of Plasmodium commonly infect human beings, of which Plasmodium falciparum is the most dangerous and Plasmodium vivax the most widespread in India.

Rust of wheat is indeed a fungal disease, caused by species of Puccinia, and it is named from the reddish brown spores that appear in streaks on the leaves and stem.

Bacillary dysentery, also called shigellosis, is caused by bacteria of the genus Shigella, which invade the lining of the large intestine and produce frequent stools with blood and mucus, along with fever and cramps; it spreads through contaminated water and food.

Escherichia coli is a bacterium whose harmful strains reach the body through drinking water or food contaminated with sewage, and the infection they produce shows itself as diarrhoea and abdominal pain, which places it among the classic water-borne illnesses along with cholera, typhoid and hepatitis A. Option A is wrong…

Asia supplies more than half of the world's tin, because the great tin belt of South East Asia runs through Myanmar, Thailand, Malaysia and Indonesia, and China is the largest single producer.

On Survey of India topographical sheets, railway lines, telegraph and telephone lines, settlement names and boundaries are printed in black, so black is the colour of such man-made linear features.

Kazakhstan is the world's largest producer of uranium and alone accounts for roughly two-fifths of global output. Its uranium comes mainly from the Chu-Sarysu and Syr Darya basins and is won by in-situ leaching, a method that dissolves the metal underground instead of digging it out.

Tropical deciduous forests are India's monsoon forests, and their trees shed their leaves for about six to eight weeks in the dry summer to save water.

Leh, in the cold desert of Ladakh, lies above 3,500 metres in the Himalayas, and its winter temperature falls far below freezing, lower than anywhere else in the list.

The calm centre of a cyclone is called the eye of the storm, a roughly circular area twenty to fifty kilometres across where the air sinks, the winds are light and the sky can even be clear.

In the mesosphere the temperature falls as one goes up, reaching about minus 100 degrees Celsius at the mesopause near 80 km, which makes it the coldest layer of the atmosphere.

Jawaharlal Nehru was arrested on 31 October 1940 for individual satyagraha against India being dragged into the Second World War without the consent of its people, and he was sentenced to four years in prison.

The Himalayas are young fold mountains, formed when the sediments of the Tethys Sea were squeezed and folded as the Indian plate collided with the Eurasian plate.