Simplify the following text for a Grade 5 native English-speaking person.
Original: The interior of South Africa is a vast , flat , and sparsely populated scrubland , the Karoo , which is drier towards the northwest along the Namib desert .
Simplified: The back of South Africa is a big and flat . It is a very populated scrubland , the Karoo , which is drier towards the northwest along the Namib desert .