Final answer:
Tassili n'Ajjer in the Sahara Desert of North Africa is known for ancient rock art with scenes featuring cows.
Step-by-step explanation:
The African region known for ancient rock art with scenes featuring cows is Tassili n'Ajjer in the Sahara Desert, North Africa. Tassili n'Ajjer is a plateau in Algeria and is famous for its rock paintings and engravings dating back as far as 12,000 years.