The _____ lies immediately above the mesosphere.

The correct answer is Option (2) → Thermosphere

Going up from the Earth's surface, the layers of the atmosphere are:

• Troposphere — the lowest layer, where weather happens

• Stratosphere — holds the ozone layer

• Mesosphere — the coldest layer, up to about 80–85 km

• Thermosphere — where the temperature rises sharply with height; it contains the ionosphere

• Exosphere — the outermost layer, merging into space

So the layer immediately above the mesosphere is the thermosphere.