2. For every single human, there are 25 million ants. How much could 25 million ants lift altogether?

3. Which is heavier: pumice stone or ironwood? Pumice stone floats in water. Ironwood sinks in water. Therefore Ironwood is heaviest.

4. How much does the skin of the average human weigh? About 4kg. The average woman’s skin weighs 3kg, the average man’s 5kg.

7. How many bones are there in the human body? 206

8. Which creature has the greatest number of bones in its skeleton?

9. 1792 Everyone knows the Eiffel tower is 324m tall, but how many steps does it have?