General Science Questions and Answers

Answer: D

Vestiges of hind limbs are present in the python, appearing as small spurs on either side of the vent.

They are remnants of the legs its ancestors had, and are used by the male in courtship. Advanced snakes such as cobras, kraits and sea snakes have lost them entirely.

Answer: C

Oyster shells are composed mainly of calcium carbonate, laid down as aragonite and calcite by the mantle of the animal.

Fish scales and shark teeth are largely calcium phosphate in the form of dentine and enamel, as are the bones of whales and other vertebrates.

Answer: C

The mature red blood corpuscle in man has no nucleus. It is extruded as the cell matures, leaving more room for haemoglobin and giving the cell its flexible biconcave shape.

The consequence is that a red cell cannot divide or repair itself, and lives only about 120 days. White cells and spermatozoa both retain their nuclei.

Answer: D

Cryogenics is the study of materials and phenomena at very low temperatures, conventionally below about −150°C.

It covers the liquefaction of gases, superconductivity and superfluidity, and its practical uses run from MRI magnets to rocket propellants.

Answer: C

Titan is the largest moon of Saturn and the second largest in the solar system, bigger than the planet Mercury.

It is the only moon with a substantial atmosphere - mostly nitrogen, denser at the surface than Earth's - and has lakes and rivers of liquid methane.

Answer: B

The membrane bounding the vacuole in a plant cell is the tonoplast.

It controls what passes between the vacuole and the cytoplasm, and it maintains the turgor pressure that keeps a non-woody plant upright. The plasma membrane bounds the whole cell, and the cell wall lies outside that.

Answer: C

Diphtheria affects the throat. The bacterium Corynebacterium diphtheriae multiplies in the upper respiratory tract and forms a thick grey membrane over the tonsils and pharynx that can obstruct breathing.

Its toxin also damages the heart and nerves. The disease is prevented by the DPT vaccine.

Answer: A

Numismatics is the study of coins, and of currency generally - including tokens, medals and paper money.

Philately is the study of stamps and lepidopterology of butterflies.

Answer: A

The bat uses sound as its eyes. It emits ultrasonic pulses and builds a picture of its surroundings from the returning echoes - a process called echolocation.

The technique is precise enough to catch a flying insect in total darkness. Dolphins and some whales use it in water; owls hunt by acute hearing but do not emit sound of their own.

Answer: A

The giant panda belongs to the bear family, Ursidae. DNA studies settled a long argument, confirming it as a true bear despite its bamboo diet.

The red panda, which is not a bear, belongs to a family of its own.