GK (Science)

Hypermetropia, or long-sightedness, is a condition where a person can see distant objects clearly but has difficulty focusing on near objects. Since the person cannot see objects nearer than 75 cm, they are suffering from hypermetropia.

An antigen is a substance that the body recognizes as foreign, triggering an immune response. This response includes the production of specific antibodies to neutralize or eliminate the antigen.

Strontium salts produce red colors in fireworks, while barium salts produce green colors. These elements are standard components used in pyrotechnics to achieve specific color effects.

Kidney stones are most commonly composed of calcium oxalate. These form when high levels of calcium and oxalate are present in the urine.

Copper reacts with moisture, carbon dioxide, and oxygen in the atmosphere to form a green layer of basic copper carbonate, known as patina.

The ionosphere contains a high concentration of ions and free electrons, which allows it to reflect radio waves back toward the Earth's surface, enabling long-distance communication.

A saturated solution is defined as a solution in which the maximum amount of solute has been dissolved at a given temperature, meaning no more solute can be dissolved.

A solar halo is an optical phenomenon produced by the refraction of sunlight through ice crystals suspended in high-altitude cirrus clouds.

The Sun's atmosphere consists of the photosphere, chromosphere, and corona. The chromosphere is the layer above the photosphere, and the corona is the outermost layer. Given the options, chromosphere is the intended answer, though corona is technically the outermost.

A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, into direct current (DC), which flows in only one direction.

Supersonic jets release nitrogen oxides into the stratosphere, which react with and deplete the ozone layer.

Jet engines operate on the principle of conservation of linear momentum (Newton's third law), where the high-speed exhaust gas ejected backward creates a forward thrust.

Baking soda (sodium bicarbonate) is used in fire extinguishers because it decomposes when heated to release carbon dioxide gas, which smothers the fire.

The pH of human blood is tightly regulated and typically ranges between 7.35 and 7.45, which is slightly basic.

White blood cells (specifically lymphocytes) are the primary components of the immune system responsible for producing antibodies to fight infections.

Silicon is the second most abundant element in the Earth's crust and is a primary component of sand (silicon dioxide).

The Beaufort scale is an empirical measure that relates wind speed to observed conditions at sea or on land.

Pure gold is defined as 24 carats, meaning it is 100% gold by mass.

Biological death is defined as the irreversible cessation of brain function, including the brain stem, which controls essential life functions.

Normal air consists primarily of nitrogen, oxygen, argon, and trace amounts of other gases. Chlorine is a toxic gas not found in normal atmospheric samples.

Autosomes are chromosomes that are not directly involved in sex determination. Humans have 22 pairs of autosomes and 1 pair of sex chromosomes (XX or XY). Mesosomes, 'lijosomes' (likely a typo), and hexosomes are not valid biological terms for chromosomes.

Bile is produced by the liver and stored in the gallbladder. It contains bile salts that emulsify fats, aiding digestion, but it does not contain digestive enzymes itself.

Elasticity is the ability of a material to return to its original shape after being deformed. Steel is more elastic than rubber because it requires a much greater force to deform it and it returns to its original shape more perfectly.