SSC CGL Previous Year Questions: General Science - 13 - SSC CGL MCQ

The aorta is the largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it bifurcates into two smaller arteries (the common iliac arteries). The aorta distributes oxygenated blood to all parts of the body through the systemic circulation.

Parathyroid hormone (PTH), parathormone or parathyrin, is secreted by the chief cells of the parathyroid glands as a polypeptide containing 84 amino acids. It acts to increase the concentration of calcium (Ca²⁺) in the blood, whereas calcitonin (a hormone produced by the parafollicular cells (C cells) of the thyroid gland) acts to decrease calcium concentration. 

Insects, and some other invertebrates, exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae

In a nuclear reaction, the total (relativistic) energy is conserved. The "missing" rest mass must therefore reappear as kinetic energy released in the reaction; its source is the nuclear binding energy.

Annihilation is the process that occurs when a subatomic particle collides with its respective antiparticle to produce other particles, such as an electron colliding with a positron to produce two photons.

In the photoelectric effect, electrons are emitted from solids, liquids or gases when they absorb energy from light. Electrons emitted in this manner may be called photoelectrons. 

A hodograph of a particle moving with constant velocity is a point, and the corresponding trajectory is a straight line. 

Aluminium oxide has a very high melting point (over 2,000°C), so it would be expensive to melt it. Instead, it is dissolved in molten cryolite, an aluminium compound with a lower melting point than aluminium oxide. The use of cryolite reduces some of the energy costs involved in extracting aluminium.

Glucose (C₆H₁₂O₆, also known as D-glucose, dextrose, or grape sugar) is a simple monosaccharide found in plants. It is one of the three dietary monosaccharides, along with fructose and galactose, that are absorbed directly into the bloodstream during digestion. 

Any of the homologous segments, lying in a longitudinal series, that compose the body of certain animals, such as earthworms and lobsters. Also called somite.

Leachate is the term for pollutants and other liquid wastes that is formed from liquids present in the waste and from external water. It percolates and contaminates ground water.

Each lung is enclosed within a cavity known as the pleural cavity . The pleural cavity is the space between the visceral and parietal layers of lungs.

Mother’s milk is the ideal food for the newborn. Mother’s mik is loaded with various nutrients like Vitamins, minerals, enzymes, growth factors, proteins, antibodies etc. 

Transcription is the process in which a particular segment of DNA is copied into RNA by the enzyme RNA polymerase. During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, anti-parallel RNA strand called a primary transcript.

Hydrochloric acid is secreted by the parietal cells present in the the stomach. The acidic pH helps in digestion of food by providing optimal pH for pepsin and gastric lipases. 

Emulsification is the process of breaking down of fat into small globules. Bile salts helps in emulsification inside the GI tract. Emulsification provides a larger surface for pancreatic lipase for digestion of fats into fatty acids and glycerol. 

Taxonomy is the branch of science that deals with the classification of organisms. 

The Newton’s disc consists of red, orange, yellow, green, blue, indigo and violet colours that appear white when it spins at high speed. The appearance is due to the concept of persistence of vision, which states that the human visual perception cannot distinguish details of high-speed movements.

Force = Mass x Acceleration=MLT^–2 

In 1900, the German physicist Max Planck introduced the idea that energy is quantized in order to derive a formula for the observed frequency dependence of the energy emitted by a black body, called Planck's law, that included a Boltzmann distribution. 

A fiber optic consists of glass threads, each of which is arranged in bundles called optical cables. It is used to transmit light signals over long distances due to repeated bouncing of light off the walls due to total internal reflection of light.

Chitin is a hard, tough substance that occurs widely in nature, particularly in the shells (exoskeletons) of arthropods such as crabs, insects and spiders. The walls of hyphae are composed of slightly different chitin. Chemically chitin is a polysaccharide, derived from glucose.

Rutherford scattering experiment concluded that alpha particles are deflected back by a positive charge concentrated in the centre of atom. Hence, the incident alpha particles very close to this positive mass (later called as nucleus) in the centre of the atom gets deflected, while if it passes through at a fair distance from this mass, then it would simply pass through.

An atom in the excited state is not stable and hence when it returns back to the ground state, it releases the energy in the form of light that it had previously gained and thus emission spectra is observed. 

Excessive secretion of thyroxine can cause an excessively high metabolic rate, which results in hypermetabolic state. It can result into an increased heart rate and elevated blood pressure. 

The concept of Greenhouse gases (GHGs) was postulated by Joseph Fourier. It was earlier in the 20th century that the scientists started exploring the relationship behind glacial periods of ice age and atmospheric CO₂ . 

In December 1984, at least 30 tons of Methyl isocyanate gas was leaked from the Union Carbide pesticide factory in Bhopal. It is one of the major industrial disasters of the world killing over 15000 people and affected more than 600,000 workers and inhabitants over the years. 

Particulate matter ( PM10) which is defined as the fraction of particles with an aerodynamic diameter smaller than 10 μm is filtered out by the process of sneezing and coughing. 

Recently scientists in China sequenced the DNA of the wild bactrian camel, to study camel's salt tolerance. Camels consume eight times more salt than cattle or sheep and have twice the blood glucose levels of other ruminants. 

The basic unit of nervous system is known as neuron. The nervous system consists of nerves, brain and spinal cord. They control the working of various organs of the body. The part of brain and spinal cord is called the Autonomic Nervous System.