Experimenting with carbon dioxide

Since carbon dioxide is denser than air, it accumulates at the...

Fish in the aquarium

Without oxygen dissolved in water, fish would die.

The Earth's atmosphere

Farther away from the Earth's surface the atmosphere gets thinner.

The Alexander Mosaic (Pompeii, c. 2nd century BC)

The mosaic depicts a scene from the Battle of Issus with the...


It contains the name of the person who would be expelled from...

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