General Science Questions and Answers

Answer: A

Golden rice is pale yellow because it is rich in beta-carotene.

It was engineered to make beta-carotene in the endosperm, which ordinary rice does not, so that the grain supplies vitamin A. It was intended to address the deficiency that causes childhood blindness in rice-eating populations.

Answer: C

One fathom is 1.8288 m, exactly 6 feet.

\[ 6 \times 0.3048 = 1.8288\ \mathrm{m} \]

The unit is used for the depth of water and comes from the Old English for the span of a man's outstretched arms.

Answer: C

There are four cups in a quart.

A quart is two pints and a pint is two cups, so 2 × 2 = 4. A US cup is about 237 ml, making the quart roughly 946 ml.

Answer: D

Pluto takes about 248 Earth years to orbit the sun once.

Its orbit is highly elliptical, carrying it from 30 to 49 astronomical units from the sun, and it is tilted 17° to the plane of the planets. It has not completed a single orbit since its discovery in 1930.

Answer: D

The rain shadow belongs to orographic rainfall.

Moist air forced up a mountain range cools and drops its water on the windward slope; the air descending the far side is already dry and warms further by compression, so the leeward side receives very little rain. The Deccan plateau lies in the rain shadow of the Western Ghats.

Answer: B

Gottlieb Haberlandt is called the father of tissue culture.

In 1902 he proposed that any plant cell should be capable of growing into a whole plant - the principle of totipotency - and made the first attempts to culture isolated cells. Gautheret achieved the first sustained cultures in the 1930s.

Answer: C

Eucalyptus is the fastest growing of the trees listed, adding two to three metres a year in good conditions.

That speed is why it is planted for pulp and fuelwood, though its heavy water use makes it controversial in dry regions.

Answer: A

Galvanised iron is coated with zinc, usually by dipping the sheet in the molten metal.

The zinc protects in two ways: it seals the surface, and being more reactive than iron it corrodes in preference even where the coating is scratched - sacrificial protection.

Answer: B

The ozone layer, in the stratosphere between about 15 and 35 km, shields the earth from the sun's harmful ultraviolet radiation.

Ozone absorbs almost all UV-C and most UV-B, which would otherwise cause skin cancer, cataracts and damage to crops and plankton. Absorbing that energy is also what warms the stratosphere.

Answer: A

Lichens are the best indicators of air pollution, particularly sulphur dioxide.

They take their minerals directly from the air and rain, having no roots and no protective cuticle, so pollutants accumulate in them. Sensitive species disappear from city centres, and the pattern of what survives maps the pollution.