How does a rhino grow horns, and what was the longest war? Try our kids’ quiz

Illustration: Hennie Haworth/The Guardian

1. Charlie, 5, asks: how does a rhino grow horns?

   1. It spends an hour every morning pushing the horn out

   2. Horns grow on rhinos the same way that fingernails grow on humans

   3. A rhino is born with full-sized horns, they don’t grow

   4. A rhino’s horn is made of bone that pushes through the skin as it grows older

2. Lilian, 9, asks: why do humans release endorphins?

   1. To alert your body to hunger

   2. To boost concentration

   3. To cause stress and alert your body to pain

   4. To relieve pain and boost moods

3. Sam, 7, asks: why do we have leap years?

   1. Because of the time it takes the Earth to orbit the sun

   2. Because the Roman emperor who February was named after wanted an extra day in his month

   3. So that we can all get an extra day of holiday every four years

   4. Because of the time it takes for the moon to orbit the Earth

4. Alice, 10, asks: what was the longest war?

   1. The hundred years war

   2. The Reconquista

   3. The cold war

   4. The Crusades

5. Faith, 9, asks: what is the largest flower in the world?

   1. The death flower

   2. The titan flower

   3. The Goliath flower

   4. The corpse flower

Solutions

1:B - Rhino horns are made of keratin, the same as our nails and hair. A rhino grows its horns in layers of keratin, like we grow our nails!, 2:D - Endorphins are a type of neurotransmitter, a chemical that carries messages. When they are released by our brains, they reduce feelings of pain and increase feelings of happiness., 3:A - Leap years have 366 days instead of 365, with a 29th day in February once every four years. We have them because it actually takes the Earth 365 and a quarter days to orbit the sun. We add all these quarters up into a full day to make sure we don’t slowly go out of sync with the seasons!, 4:B - The so-called Reconquista was a 781-year period of conflict from 711 to 1492, when Christian kingdoms in Spain and Portugal fought with the Muslim Moors for control of the Iberian peninsula., 5:D - The largest individual flower in the world is Rafflesia arnoldii. It is native to Indonesia and it grows to be nearly 1 metre wide! It is nicknamed the corpse flower because it has a strong smell of rotting flesh that attracts insects that pollinate it. Yuck!

Scores

1. 4 and above.

2. 3 and above.

3. 2 and above.

4. 0 and above.

5. 1 and above.

Molly Oldfield hosts Everything Under the Sun, a weekly podcast answering children’s questions, out now as a book.

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• This article was amended on 22 November 2022 to clarify the text of the solution to question four.