Numbers of the Earth system

Exercise and reference answers

Questions

1. Answer

   78

   Question

   Percentage of nitrogen in the air

2. Answer

   21

   Question

   Percentage of oxygen in the air

3. Answer

   30

   Question

   Latitude in degrees where air sinks to form highs

4. Answer

   5

   Question

   Interacting spheres that make up the Earth system

Instructions

Type the number only.

Explanation