The Ultimate Science Challenge

Question 1 / 10

Question 1

What is the chemical symbol for water?

1
O2
2
H2O
3
CO2
4
NaCl

Learn more: The Ultimate Science Challenge

NASA Science publishes accessible explainers on physics and Earth systems.

Treat wrong answers as study prompts — review PubChem and peer-reviewed summaries for chemistry and biology topics.

Try Space & Cosmos and Human Body Facts.

Sources & further reading