General Science Questions (MCQs) for Competitive Examinations

Notes:
Quenching is a process in which absorbed light energy is dissipated as heat and does not take part in photochemistry. The phenomenon involves quenching of chlorophyll a fluorescence, which is induced under steady-state illumination.

Notes:
In most fish, the heart consists of four parts, including two chambers and an entrance and exit. The first part is the sinus venosus, a thin-walled sac that accumulates blood from the fish’s veins before permitting it to flow to the second part, the atrium. The atrium is a large muscular chamber, present as a one-way passage, that sends blood to the third part, the ventricles. The ventricle is a thick-walled, muscular chamber that pumps the blood, first to the fourth part, bulbus arteriosus. The bulbus arteriosus is a large tube, and then out of the heart, which attaches to the aorta, through which blood flows to the gills for oxygenation.

Notes:
Sponges are aquatic, mostly marine, primitive multicellular animals that are sessile, plant-like animal are fixed to some submerged solid rock or shell and are incapable of any movement. They come under Porifera phylum. The Porifera are exclusively marine except for a single family of fresh water species.

Notes:
PM-10 is a particulate matter having an aerodynamic diameter of less than 10 ?m. Particles larger than 10 microns tend to be filtered out in the nose and therefore do not enter the respiratory tract.

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Taenia (Tapeworm), Fasciola (Liver fluke) are examples of Platyhelminthes, mostly parasites that live in other animals including animals. Some are freeliving forms, mainly aquatic-marine or freshwater. Their bodies remain externally covered by cilia or cuticle.

Notes:
The process of photosynthesis occurs when green plants use the energy of light to convert carbon dioxide (CO2) and water (H2O) into carbohydrates. Light energy is absorbed by chlorophyll, a photosynthetic pigment of the plant, while air containing carbon dioxide and oxygen enters the plant through the leaf stomata.

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A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids. It refers to the use of wood tannins from oak in tanning animal hides into leather.

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Mostly medicinal herbs grown from 30 to 90 cm in height. They reach up to 30 cm in diameter.

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All verteberates have notochord, body cavity and gills in their embryonic stage or adult stage but not have haemocoel. It’s presence is well marked in the members of phylum in Arthopoda.

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Oxygen liberated during photosynthesis comes from the splitting or hydrolysis of water in the green plants. Cornelius van Niel experimentally proved for the first time that the oxygen liberated during photosynthesis comes from water and not from carbon dioxide. Oxygen is expelled out of plants and Hydrogen is used to reduce Carbon dioxide to produce carbohydrates.