I believe the answer is 4. During the reign of Askia Muhammad, the Songhai empire reached its greatest size. Askia Muhammad was an emperor, military commander, and political reformer of the Songhai Empire in the 15th century. His rule resulted in trade with Europe and Asia, building of lots of schools, and spread of Islam through his empire. Hope this helps! Please let me know if I'm wrong :)
Immunodeficiency disorders prevent your body from fighting infections and diseases. This type of disorder makes it easier for you to catch viruses and bacterial infections.