General Science Questions and Answers

Answer: D

Natural rubber comes from Hevea brasiliensis, the Para rubber tree of the Amazon.

Its latex is tapped by cutting a spiral groove in the bark. Seedlings smuggled to Kew in 1876 established the plantations of South-East Asia, which now supply most of the world's natural rubber.

Answer: C

The study of insects is entomology, from the Greek entomon.

Insects are the largest class of animals, with about a million described species and probably several times that undescribed. Ichthyology covers fish and anthropology human societies.

Answer: A

Dmitri Ivanovsky discovered viruses in 1892, showing that the agent of tobacco mosaic disease passed through a filter fine enough to hold back all bacteria.

Beijerinck repeated the work in 1898 and named it a contagious living fluid; Stanley crystallised the virus in 1935.

Answer: C

Round bacteria are cocci (singular coccus), from the Greek for berry.

They occur in pairs as diplococci, chains as streptococci and clusters as staphylococci. Rod-shaped bacteria are bacilli, comma-shaped are vibrios and spiral are spirilla.

Answer: C

Natural petroleum is found as crude oil - a dark, viscous mixture of hydrocarbons trapped in porous rock beneath an impermeable cap.

Petrol, kerosene, diesel and the rest are obtained from it by fractional distillation at a refinery; none of them occurs in the ground as such.

Answer: D

The United States consumes the most petroleum, about 20 million barrels a day - roughly a fifth of world consumption.

China is second and India third. Saudi Arabia is among the largest producers but a much smaller consumer.

Answer: C

Carbon monoxide is not a greenhouse gas. A greenhouse gas must absorb infrared radiation, which needs a molecule whose dipole moment changes as it vibrates.

Carbon monoxide absorbs very weakly and lasts only a few months in the atmosphere. Carbon dioxide, methane and water vapour are all effective greenhouse gases.

Answer: A

PVC stands for polyvinyl chloride, made by polymerising vinyl chloride, CH₂=CHCl.

Rigid PVC is used for pipes and window frames; adding a plasticiser makes it flexible for cable insulation and sheeting. It is the third most produced plastic in the world.

Answer: D

Canada is the country listed without cryogenic engine technology.

Only a handful of nations have mastered it - the United States, Russia, France, Japan, China and India. India's first indigenous cryogenic stage flew successfully on GSLV-D5 in January 2014.

Answer: A

The GSLV Mark III is India's heaviest rocket, about 640 tonnes at lift-off and 43 metres tall.

It can place four tonnes into geostationary transfer orbit or eight into low earth orbit. It launched Chandrayaan-2 and is the vehicle chosen for the Gaganyaan crewed mission.