Simplify the following text for a Grade 13 native English-speaking person.
Original: Along with several Interandean Valles , they are typically dominated by deciduous woodland , shrub and xeric vegetation , reaching the extreme in the slopes near the virtually lifeless Atacama Desert .
Simplified: Along with many Interandean Valles , they are normally ruled by deciduous woodland , shrub and xeric vegetation , reaching in the slopes near the mostly lifeless Atacama Desert .