For the last ............. .......... ........... the proportion of gases in the atmosphere has been much the same

• 200 million years

• 800 million years

• 1 billion years

• 200 billion years

The current proportion of gases is approximately

• 20% nitrogen, 80% oxygen and small proportions of various other gases.

• 80% nitrogen, 20% oxygen and small proportions of various other gases.

• 70% nitrogen, 30% oxygen and small proportions of various other gases.

• 30% nitrogen, 70% oxygen and small proportions of various other gases.

The early atmosphere of Earth contained gases due to ...

• Plant life

• Algae

• Volcanic activity

• Dinosaurs

The Early atmosphere of Earth was similar to that of ................... .... .............. today

• Mars and Venus

• Neptune and Mercury

• Uranus and Mars

• Venus and Jupiter

What was the composition of Earth's early atmosphere?

• Mostly methane, little to no carbon dioxide

• Mostly oxygen, little to no carbon dioxide

• Mostly nitrogen, some oxygen

• Mostly carbon dioxide, little to no oxygen

True or false. Volcanoes produced carbon dioxide, water vapour, methane and ammonia.

• True

• False

Oceans could only form when............

• the boiling point of water changed

• the melting point of water changed

• the Earth cooled enough

• photosynthesis began

The carbon dioxide in the early atmosphere reduced due to it .........

• dissolving in oceans

• forming carbonates in water

• forming sedimentary rocks such as limestone

• photosynthesising plants

• All of the previous points

Oxygen in the atmosphere increased due to .....

• Respiration

• Photosynthesis

• Distillation

• Evaporation

Which is the correct equation for photosynthesis?

• carbon dioxide + oxygen → glucose + water

• carbon dioxide + water→ glucose + oxygen

• carbon dioxide + glucose → water + oxygen