Biology Questions and Answers

Answer: A

Shifting cultivation is not a method of ex situ conservation - it is a farming practice, and one that destroys habitat.

Ex situ conservation keeps species outside their natural home: botanical gardens, zoos, seed banks, field gene banks and cryopreservation. In situ conservation protects them where they live, in parks and sanctuaries.

Answer: A

The scientific name of man is Homo sapiens, meaning wise man.

Under the binomial system the first word is the genus and the second the species; the genus is capitalised, the species is not, and both are italicised. Rana tigrina is the Indian bullfrog and Felis domestica the cat.

Answer: D

An adult human has about 5 to 6 litres of blood, roughly 7 to 8 per cent of body weight.

Men average nearer 5.5 litres and women about 4.5. Losing more than about a fifth of it causes shock.

Answer: A

The prokaryotes have no nuclear membrane.

Their DNA lies free in the cytoplasm as a single circular chromosome in a region called the nucleoid. Bacteria and archaea are prokaryotes; protozoa are eukaryotes and do have a nucleus.

Answer: B

The correct statement is that the atrioventricular valves are supported by the chordae tendineae, which stop them turning inside out when the ventricles contract.

The tricuspid valve lies between the right atrium and right ventricle and the mitral between the left atrium and left ventricle - the reverse of what two of the other options say.

Answer: C

Organisms that feed on the droppings of others are coprophagous, from the Greek kopros, dung.

Dung beetles and many termites and rodents are coprophagous. Rabbits eat their own soft pellets to extract nutrients released by the second passage through the gut.

Answer: C

Theophrastus is called the father of botany.

A pupil of Aristotle who succeeded him at the Lyceum, he wrote Historia Plantarum and De Causis Plantarum around 300 BC, describing some five hundred plants and classifying them by form and habit.

Answer: B

White blood corpuscles combat infection.

Neutrophils and macrophages engulf bacteria; lymphocytes make antibodies and destroy infected cells. There are only about 4,000 to 11,000 per cubic millimetre against five million red cells, but their number rises sharply during infection.

Answer: B

Floriculture is the cultivation of flowering and ornamental plants.

It covers cut flowers, potted plants, bedding plants and nursery stock. Agronomy deals with field crops and phenology with the timing of seasonal events.

Answer: D

Arthropoda is the largest phylum, with over a million described species - about 80 per cent of all known animals.

It includes insects, crustaceans, arachnids and myriapods, united by a jointed exoskeleton of chitin and jointed limbs. Insects alone outnumber every other group of animals combined.