General Science Questions (MCQs) for Competitive Examinations

Notes:
Turner syndrome is a rare chromosomal disorder characterized by partial or complete loss (monosomy) of one of the X chromosomes that affects females. Individuals with Turner syndrome have only 45 chromosomes, including just a single X chromosome. This monosomic has a chromosome complement of 44 autosomes and one X chromosome (44+XO). The abnormal condition probably originates from exceptional egg or sperm with no X chromosome.

Notes:
Greenhouse gases that occur both naturally and from human activities include water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ozone (O3). These gases contribute to atmospheric warming when they absorb infrared radiation emitted by the solar-warmed Earth and transfer their extra energy to the surrounding atmospheric gases.

Notes:
Calyptrogen is a layer of rapidly dividing cells at the tip of a plant root, from which the root cap is formed. It occurs in grasses and many other plants. The root cap is formed by several layers of cells that envelop the root tip externally. This covering of cells, of which the outermost ones are dead, envelops and protects the growing tip of root.

Notes:
Barani area are traditionally rain-fed areas. These are any low rain area where the rain-fed dry farming is practiced. Bagar tract, the dry sandy tract of land on the border of Rajasthan state adjoining the states of Haryana and Punjab, is an example of Barani land.

Notes:
Both polio and chicken pox are caused by virus. Poliomyelitis, often called polio or infantile paralysis, is an infectious disease caused by the poliovirus; while, Chickenpox, also known as varicella, is a highly contagious disease caused by the initial infection with varicella zoster virus (VZV).

Notes:
Humming birds are birds that comprise the family Trochilidae. They are among the smallest of birds, most species measuring in the 7.5–13 cm (3–5 in) range. Indeed, the smallest extinct bird species is a humming bird, the 5-cm Bee Humming bird. These birds being the smallest are, capable of flying both in forward and back direction.

Notes:
In menstrual cycle 19-21 days stands for the fertilizing period also called danger period. After ovulation on 14th day chances of contraption are at their highest with well developed endometrium for implantation. This is the time in the menstrual cycle when progesterone should be at its peak for the month and when estrogen should be at the height of its luteal plateau.

Notes:
Sulphur dioxide (SO2) is considered as the most serious single air pollutant causing health hazard, obstructing breathing. It always leads to airways inflammation, eye irritation, psychic alterations, pulmonary oedema, heart failure and circulatory collapse. It is also responsible for acid rain.

Notes:
Stomata are tiny openings or pores in plant tissue that allow for gas exchange. Stomata allow a plant to take in carbon dioxide, which is needed for photosynthesis. They also help to reduce water loss by closing when conditions are hot or dry. Stomata look like tiny mouths which open and close as they assist in transpiration.

Notes:
Silk worms are the larva of a moth (Bombyx mori) native to Asia that spins a cocoon of fine, strong, lustrous fiber that is the source of commercial silk. Silkworms feed on the leaves of the mulberries (genus- Morus) and sometimes on the Osage orange (Maclura pomifera).