1 – Tobacco

Ranked by human death toll, the tobacco plants (multiple species in the genus Nicotiana) are easily the most notorious killers. These herbs cause one in ten adult deaths every year.

2 – Hemlock

Coniine, the toxin in the poison hemlock that killed Socrates, paralyses the respiratory system. The cicutoxin in water hemlock causes seizures with violent muscle contractions.

3 – Oleander

Oleander is a true heart- stopping beauty. If you chow down on this surprisingly common backyard shrub, however, it’s likely to send you into cardiac arrest.

4 – Gympie-gympie

This stinging tree species lurks in northern Australia and Indonesia. It penetrates your skin with tiny glass-like silicon hairs, covered in a deadly neurotoxin.

5 – Giant pitcher plant

These Philippines natives are trouble for insects and rodents. Lured by nectar, victims – or nutrient sources – slip into a vat of acid with ribs that block escape.

Octopuses are the superheroes of the animal kingdom, with so many amazing abilities and adaptations that it begins to look greedy. They can solve mazes, open screw-top jars and use tools. They can walk, they can swim and they can even jet propel themselves at high speed. They can change colour, imitate other animals, squirt ink, inject poison and jettison their own legs. When you can do all that, who cares if you can predict football results or not?

Although they are molluscs, octopuses don’t have a shell or bones and the only hard part of their body is a small beak, made of keratin. This allows them to squeeze through extremely small gaps – an octopus a metre across can pass through a tube the size of a 50 pence coin. Octopuses mainly eat crabs and small fi sh that they winkle out of crevices in rocks and coral reefs, but they can also tackle small sharks by enveloping the shark’s gill openings and suffocating them.

Octopus blood uses a greenish-blue copper pigment called haemocyanin, instead of the iron-based haemoglobin in our own blood. Haemocyanin can’t carry as much oxygen as haemoglobin, but it is actually more efficient at low oxygen concentrations and in cold water. Despite this, octopuses have poor circulation and quickly run out of energy. This may be one of the reasons for their intelligence – theydon’t have the stamina for a prolonged chase and must rely on their cunning. Male octopuses die almost immediately after mating. The females are even bigger martyrs. They guard their 20,000 eggs for a month and rather than leave the nest to hunt, they will eat some of their own legs. After that, the female dies and the eggs hatch into babies approximately the size of a walnut.

Ant strength is due to their small size. An ant worker can lift an object weighing five to ten times its weight and can drag a 20-50 times heavier object, whereas humans can rarely lift their own weight. However, ant muscles are no stronger than human muscles (in terms of force per cm2), but the small size of ants (one to five milligrams) gives them an advantage on how much muscle force they can produce. As the size of an organism increases, its body mass increases at a much greater rate than the cross-sectional area of muscles, so that the muscles of larger organisms have proportionately more mass to lift. A small size means ants have proportionately more muscle (in terms of cross-sectional area) that they can use to lift heavy objects. If we were as small as an ant, we could do the same.

Answered by Dmitri Logunov.

Our home planet is about 4.5 billion (4,500 million) years old. This date is based on samples from the Earth, meteorites and the moon, which all come from when the Earth first formed. Scientists have looked at radioactive chemicals in the rocks which react into new chemicals over a certain period of time. By working out how many times this reaction has taken place, scientists are then able to determine the age of the rock.

Answered by David Gelsthorpe, Manchester Museum.

Ruby is the red variety of the mineral corundum (Al2O3). In the structure of atoms which makes up a ruby, small amounts of chromium (normally about 1 per cent) can replace aluminium. In pure corundum, which is colourless, all the energy levels in the aluminium and oxygen are occupied by paired electrons. In chromium, however, six electrons are available for bonding but only three are required – this leaves partially filled energy levels. Electrons in these can absorb energy from visible light. The energy remaining corresponds to red light in the spectrum. Simultaneously ruby will absorb energy in the ultraviolet and re-emit it in the visible part of the spectrum as red light (ie fluorescence). The red colour is therefore ultimately caused by the presence of chromium.

Answered by Brian Jackson, principal research curator of Mineralogy at National Museums Scotland.

Tortoises live so long because they grow at a steady rate and hibernate. Tortoises, like other reptiles, are cold blooded, or ectothermic, so they need to ‘warm up’ by absorbing heat from their surroundings to keep active. In winter, when food is scarce and the temperature falls, tortoises in the wild stop eating, their breathing and heartbeat both slow and they go into a deep sleep. Studies show that tortoises grow rapidly during their early years and continue to grow at a steady rate that decreases with age. There is evidence of extreme age, although some reports of tortoises living over 150 years have proved unreliable, as has counting the growth rings of shell plates.

Answered by Sandra Chapman, Palaeontology Department, National History Museum London.

Asked by Jonny Osmond

This depends on the species. In the case of the cosmopolitan pest species that breeds indoors, like American and German cockroaches, both sexes have well-developed wings and are able to fly. Male oriental cockroaches, however, have wings reduced in length and the females just have small buds, so neither sex can fly. Some tropical species like the giant hissing cockroach from Madagascar are wingless in both males and females. In Britain we have three species of native cockroach all of which have well-developed wings, and so are capable of flight.

Phil Rispin, Curatorial assistant of Etymology at The Manchester Museum

Actually lakes do have tides but they are not usually big enough to see. Tides are changing sea levels mostly caused by the moon’s gravitational pull on the Earth. As the moon draws the sea towards it in one place in the world, the sea moves away from the coast somewhere else. The change in sea level depends on the size and location of the sea, how deep it is and the slope of the ocean floor at the coast.

Lakes experience the same gravitational pull, but because they are much smaller than seas their tides are also smaller and so more difficult to detect.

Answered by Kate Mulcahy.

Asked by Ian Sanders

There has been a series of ice ages over the past million years or so. Sometimes this whole period is referred to as the ‘ice age’, although it has included many individual glacial periods that alternated, every hundred thousand years or so, with warm periods called interglacials. More accurately, the ‘last ice age’ refers to the most recent of these glacial episodes. This global descent into cold climate started about 100,000 years ago and ended 11,700 years ago. That whole period can be regarded as the last ice age, though it was also complex, with varying climate.

The coldest part, when massive glaciers extended as far south as Britain, happened between 25,000 and 20,000 years ago; we call it the last glacial maximum. When will the next ice age be? Past interglacials have been quite variable in length; ours so far has lasted 11,700 years. According to geophysicists, our interglacial still has several thousand years left to run, after which another ice age may well begin. However, human influence could change everything. The climate system is very complex and delicate, and global warming could hugely affect the onset of the next ice age.

Adrian Lister, Palaeontology, NHM London