General Science Questions (MCQs) for Competitive Examinations

Notes:
Damping off is a horticultural disease or condition, caused by a number of different pathogens that kill or weaken seeds or seedlings before or after they germinate. Pythium, a genus of parasitic oomycete, are most often responsible for damping-off. Along with Rhizoctonia solani, attacks by Pythium are most associated with producing roughly circular patches of dead seedlings.

Notes:
Vitamins A, D, E, and K are the fat-soluble vitamins. Unlike water-soluble vitamins, these vitamins dissolve in fat and are stored in body tissues. Too much vitamin A, D, or K (Hypervitaminosis) can lead to increased levels that are unhealthy and can cause health consequences. For example, too much vitamin A can lead to birth defects.

Notes:
Pyria, or periodontal disease, is a progressive gum disease characterized by inflammation resulting from the toxins found in plaque. It leads to bleeding of the gums. If allowed to progress, Pyria begins to destroy underlying tissue, which may eventually lead to premature tooth loss.

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‘Survival of the fittest’ is a phrase that originated from Darwinian evolutionary theory as a way of describing the mechanism of natural selection. Herbert Spencer first used the phrase, after reading Charles Darwin’s On the Origin of Species, in his Principles of Biology (1864), in which he drew parallels between his own economic theories and Dar-win’s biological ones.

Notes:
Bonsai is the art of aesthetic miniaturization of trees and plants in containers. A bonsai plant is not a dwarf plant but equal to the full sized flowering plant. The main objective of bonsai plants is to create a tree or plant, and even landscapes, in miniature at household level.

Notes:
Bone is a composite of proteins such as collagen and minerals such as calcium. Calcium phosphate is the major component of bones and teeth. Except for small portions of the inner ear, all hard tissues of the human body are formed of calcium phosphate. Collagen gives the bones a soft framework, while calcium makes them hard and strong.

Notes:
Radon is used in radiotherapy for cancer treatment. Radon is the heaviest known gas, is radioactive and is essentially inert. At ordinary temperatures, radon is a colorless gas, but when it is cooled below its freezing point it gains stunning phosphorescence. One problem with radiation therapy is that it often kills healthy tissue alongside cancerous tissue.

Notes:
Fermentation is the process by which complex organic compounds, such as glucose, are broken down by the action of enzymes into simpler compounds in the absence of oxygen (anaerobic). Yeasts can convert sugars to alcohol and carbon dioxide by fermentation. Fermentation is used to produce wine, beer, yogurt and other products.

Notes:
An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach. When excessive amounts of acids are produced in the stomach the natural mucous barrier that protects the lining of the stomach can damage the esophagus in people with acid reflux. Antacids contain alkaline ions that chemically neutralize stomach gastric acid, reducing damage and relieving pain.

Notes:
In molybdenum-deficient plants grown in the presence of nitrate, molybdenum is required for the synthesis of nitrate reductase. Molybdenum deficiency results in the decrease of free amino acids in the plants in comparison to normal plants.