RRB Group D GK Questions 2026

Khusrau lived in the thirteenth and fourteenth centuries and was the disciple of the Chishti saint Nizamuddin Auliya of Delhi.

Salinity is the quantity of dissolved salts in a kilogram of sea water, expressed in parts per thousand, and isohalines map its distribution; the open ocean averages about 35 parts per thousand, while enclosed seas with high evaporation such as the Red Sea are far saltier and seas fed by…

The earth's orbit is an ellipse, so its distance from the sun changes through the year; at perihelion, about 3 January, the earth is nearest the sun, which is why the northern winter half of the year is slightly shorter than the summer half.

A contour, whose technical name is isohypse, joins all points standing at the same height above sea level and is the chief means of showing relief on a topographical sheet; contours drawn close together mean a steep slope, contours far apart a gentle slope, and contours that merge indicate a…

In Alfred Weber's least-cost theory of industrial location, isodapanes are drawn through all points at which the total transport cost, for assembling the raw materials and for distributing the finished product, is the same; the innermost isodapane marks the area of least total cost, where the plant should be sited.

The Isthmus of Panama joins North and South America and separates the Caribbean Sea from the Pacific, and the Isthmus of Suez joins Africa to Asia; both have been cut by canals precisely because they are narrow.

Magnetic declination is the angle between true north and magnetic north, and along the agonic line that angle is zero, so a compass needle there points to true north.

Isoseismal lines join points at which the shaking of an earthquake was felt with the same intensity, and because intensity falls away from the source, they are drawn as roughly concentric closed curves around the epicentre, the point of the surface vertically above the focus.

The Greek bathos means depth, so isobaths are the depth contours of a bathymetric chart; the 200 metre isobath is conventionally taken as the outer edge of the continental shelf.

An isohel, from the Greek helios for the sun, joins places that receive sunshine for an equal number of hours, and such maps are used in studies of solar energy potential and of crop seasons.

The word comes from the Greek hyetos, meaning rain, so an isohyet joins all places on a map that receive the same amount of rainfall in a given period; rainfall distribution maps of India, which show the 200 centimetre and 50 centimetre lines, are drawn with isohyets.

Twelve pairs of cranial nerves arise from the brain and serve the head and neck, among them the optic nerve of sight, the auditory nerve of hearing and the vagus, the longest cranial nerve, which reaches the heart and the abdomen; thirty-one pairs of spinal nerves arise from the spinal…

The hyoid is a U-shaped or horseshoe-shaped bone lying in the front of the neck below the lower jaw; it is held in place only by muscles and ligaments and forms no joint with any other bone, which is why it supports the tongue and helps in speech and swallowing.

The thyroid is a butterfly-shaped gland in the neck, in front of the windpipe, and is the largest of the ductless or endocrine glands; it secretes thyroxine, for which iodine is essential, and the hormone controls the rate of metabolism, growth and development.

Each kidney contains about a million nephrons, and each nephron consists of a Bowman's capsule enclosing a knot of capillaries called the glomerulus, followed by a tubule in which useful substances are reabsorbed; together they filter the blood and form urine.

The islets of Langerhans are patches of endocrine tissue in the pancreas, and their beta cells secrete insulin, which lowers the level of glucose in the blood by helping cells take it up and by storing the surplus as glycogen; a lack of insulin causes diabetes mellitus.

The cerebellum lies behind and below the cerebrum and coordinates voluntary muscular activity, so it keeps the body balanced and the posture steady; damage to it causes a staggering walk even though the muscles are strong.

The Austrian scientist Karl Landsteiner discovered the A, B and O blood groups in 1901 and received the Nobel Prize for Physiology or Medicine in 1930 for the work; he was also associated with the discovery of the Rh factor, named after the rhesus monkey.

Red blood cells are produced in the red bone marrow, lose their nucleus on maturing and survive roughly four months, after which they are broken down in the spleen, which is accordingly called the graveyard of red blood cells; the iron released from their haemoglobin is used again.

The sino-atrial node is a small patch of specialised muscle tissue in the wall of the right atrium near the opening of the superior vena cava, and it generates the impulse that sets the rate of each heartbeat without any outside stimulus, which is why it is called the pacemaker.