Nature Quiz

Answer: Can kill a horse in minutes through intestinal damage and respiratory paralysis. All parts of this plant are toxic, containing alkaloids with a paralysing action. The lethal dose is low: a few grams of leaves are enough to kill a small dog, and 300 g can kill an adult bovine.

Answer: 150 years and more. The giant Galápagos tortoise can live over 150 years, sometimes 175. Harriet, a tortoise brought back by Darwin, reportedly died in 2006 aged an estimated 175 years. She had seen a few things.

Answer: Ebony. Ebony wood is so heavy and dense that it does not float on water, sinking straight to the bottom like metal.

Answer: Reflection and refraction of light. Rainbows appear when sunlight is refracted (bent) and reflected by water droplets suspended in the air.

Answer: 1.5 m/s. Two opposing currents flow through it: the surface current (flowing into the Mediterranean at 1.5 m/s) and the deep current (flowing out). When Mediterranean waters reach the Atlantic Ocean they sink along continental slopes and spread at depths of over 1,000 m.

Answer: The gorilla. The lowland gorilla and the mountain gorilla are the largest and most powerful primates alive today.

Answer: Laurel. The laurel wreath was awarded to victors at the games and to poets, symbolising honour and success.

Answer: Golden poison frog. The golden poison frog (Phyllobates terribilis) secretes batrachotoxin, one of the most potent toxins in the animal kingdom. A single frog carries enough poison to kill several adults.

Answer: The green chlorophyll fades, revealing yellow and orange pigments that were already there. With shorter days, the tree stops making chlorophyll. The yellow pigments, hidden all summer, finally show. The reds, on the other hand, are produced in autumn.

Answer: Sugary sap made by the leaves. Xylem carries raw sap, water and minerals, upwards, while phloem distributes sugar-laden sap to the roots, fruit and buds. This is the network that aphids and cicadas tap into to feed.

Answer: Lesser hemlock. Fool's parsley (Aethusa cynapium) is a highly poisonous plant, also known as « fool's parsley » or « dog parsley », because its leaves can be mistaken for those of parsley. It belongs to the same family as hemlock, but is generally considered less toxic. However, ingesting it can cause potentially serious digestive and neurological symptoms.

Answer: Cedar. The cedar features on the Lebanese flag.

Answer: Mycorrhiza. In mycorrhiza, the fungus helps the plant absorb water and minerals from the soil, in exchange for sugars produced through photosynthesis. Over 80% of land plants benefit from this.

Answer: About 70%. Nearly 70% of the world's fresh water is locked up in polar ice, making it the planet's largest reserve of fresh water, though not directly accessible.

Answer: Nodules housing nitrogen-fixing bacteria. These nodules are tiny fertiliser factories. Their pink colour comes from leghaemoglobin, a protein related to our own haemoglobin, which protects the nitrogen-fixing enzyme from too much oxygen.

Answer: Auxin. Lit from one side, the plant moves auxin to its shaded side, where cells lengthen more, so the stem curves towards the light. Charles Darwin and his son showed as early as 1880 that it is the tip of the young shoot that senses the light.

Answer: A date palm seed. Nicknamed 'Methuselah', this Judean date palm, an extinct variety, grew from a seed that had stayed dormant for two thousand years. Other ancient seeds have since produced a small grove, which has even yielded dates.

Answer: By catching sea fog with their needles. Pacific coastal fog settles as droplets on the needles, drips to the ground or is even absorbed directly by the foliage. This helps water the crowns of trees over 110 metres tall, where water from the roots struggles to reach.

Answer: It senses the chemical scents released by nearby plants and grows towards them. A 2006 study showed that young dodder seedlings head towards a tomato plant's volatile compounds and even choose the most rewarding host. Once in contact, it coils round and pushes tiny suckers into its tissues.

Answer: They lock up a lot of carbon in their sediments, often faster than a land forest. The roots and debris of these plants pile up in oxygen-poor sediments, where they decompose very slowly. Carbon can stay locked there for centuries: it is called 'blue carbon'. Yet these meadows are shrinking in many parts of the world.