(4) Five Explanation: Earth has five primary layers, which are the troposphere, stratosphere, mesosphere, thermosphere and exosphere. From the Earth upwards, those layers are: Troposphere: 0 to 12 km: Stratosphere: 12 to 50 km; Mesosphere: 50 to 80 km; Thermosphere: 80. to 700 km; Exosphere: 700 to 10,000 km.