Science & Mathematics Questions & Answers

An eye that suffers from myopia as well as from hypermetropia is said to suffer from presbyopia. A person with this defect cannot see objects distinctly placed at any distance from him. To correct this defect, a person is prescribed bifocal lens that has both types of lenses — convex and concave.

This is the process of using an instrument called polygraph, which is also popularly known as a lie detector.

Which is the planet farthest from the sun? Pluto, of course. But, some recent findings suggest that Pluto is not a planet at all. It seems Pluto could actually be a comet, reports the National Geographic website. Basically, it is Pluto’s small size that has got it into trouble. It has a diameter of approximately 1,420 miles or 2,280 kilometers. …

The breeding, rearing, and transplantation of fish by artificial means is called pisciculture, in other words, fish farming. It is the principal form of aquaculture, while other methods may fall under mariculture. It involves raising fish commercially in tanks or enclosures, usually for food. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a …

Photosynthesis is the process by which green plants make food for themselves-and, indirectly, for all animals, including human beings. Without it, life as we know it on this earth would be impossible. In photosynthesis plants combine water and salts in the soil, and carbon dioxide in the air to build up organic compounds, such as sugar starch and proteins. To …

The compound zinc oxide (ZnO) is called philosopher’s wool. Alchemists, as part of their rituals, would burn zinc in air and collect the residue, which formed into white woolly tufts. They called it lana philosophica in Latin, meaning philosopher’s wool. Zinc oxide has many uses: as white pigment in paints, component in zinc ointment for treating skin diseases, material in …

It is a feeling of fatness, much after a person has lost weight. The overweight person’s mind is still not accustomed to the new, leaner body, and continues to perceive the body as fat. This perception is called phantom fat. That is because the mind is not yet used to the internal body image. It is easier to lose fat …

Pesticide remains in vegetables can cause neurological and blood disorders, lung ailments and affect the reproductive system of women. Agriculture workers are as prone to risks as consumers. Prolonged exposure to raw pesticides (common among agricultural workers) or consumption of pesticide-infected vegetables can result in leukaemia and cancer of the skin, lips, stomach and prostrate. Complaints of chronic fatigue, excessive …

In cold countries, the soil freezes hard in winter. In summer, the top few centimeters may thaw, while lower down the stays frozen. This permanently frozen soil is called permafrost. Several extinct woolly mammoths, which died about 45,000 years ago, have been dug out of the permafrost in Siberia. The meat of one of them, preserved in this natural refrigerator, …

There are two types of immunity for infectious microorganisms: active immunity and passive immunity. Passive immunity is provided by artificial means such as injections of antibodies and vaccines. The agents used for passive immunity include antibodies from humans or animals.