General Science

The average normal human body temperature is about 37°C, although it varies with the individual, time of day and method of measurement.

Autotrophs are organisms capable of producing their own food, generally through photosynthesis or chemosynthesis. Green plants are the most familiar photosynthetic autotrophs.

Ethylene is a plant hormone that promotes fruit ripening. Commercial ripening practices use controlled ethylene exposure; unsafe chemicals such as calcium carbide are not the same as ethylene-based ripening.

The age of a tree is commonly estimated by counting its annual growth rings in the trunk. This method is called dendrochronology.

Sir Frank Whittle developed the first practical turbojet engine in Britain. His pioneering jet-engine work was patented in 1930.

Jupiter has the fastest rotation of the eight planets, completing one rotation in about 9 hours 56 minutes. Its rapid rotation contributes to its equatorial bulge.

Beriberi results primarily from deficiency of vitamin B1 (thiamine). It can affect the nervous system and cardiovascular system.

The famous Dancing Girl of Mohenjo-daro is a small bronze statue made using the lost-wax technique. It dates to the mature Harappan period, around the 3rd millennium BCE.

Rabies is caused by the rabies virus, a neurotropic virus transmitted mainly through the saliva of infected mammals, especially by bites.

Washing soda is sodium carbonate decahydrate (Na₂CO₃·10H₂O). Sodium bicarbonate is baking soda, not washing soda.

Gregor Mendel established the basic laws of heredity through pea-plant experiments. His work, published in 1866, laid the foundation of modern genetics.

SONAR uses reflected ultrasonic waves; the returned signal is an echo used to determine distance or depth. The principle is therefore reflection of sound.

Human skin is commonly described as having three layers: epidermis, dermis and the subcutaneous/hypodermal layer. The epidermis is the outermost layer.

Nicolaus Copernicus proposed the heliocentric model in which Earth and the other planets revolve around the Sun. His major work De revolutionibus appeared in 1543.

The medulla oblongata contains important autonomic centres, including the vomiting centre/reflex pathways. It also regulates vital functions such as breathing and cardiovascular activity.

In the ABO system, O negative red blood cells are commonly called the universal donor type because they lack A, B and Rh(D) antigens. The basic option “O” refers to this group.

Helioseismology studies the internal structure and dynamics of the Sun through its oscillations, much like seismology studies Earth’s interior using seismic waves.

Uranus appears blue-green because methane in its atmosphere absorbs red wavelengths, leaving more blue-green light to be scattered and reflected.

The blue whale is the largest animal known to have lived and is the largest living animal today. Adults can exceed 25–30 metres in length.

NASA’s Parker Solar Probe became the first spacecraft to fly through the Sun’s outer atmosphere, the corona, in 2021.