Concept:The Five Pillars of Islam are the five basic acts of worship.Explanation:The Five Pillars in order are:1. Shahadah (Faith)2. Salat (Prayer)3. Zakat (Almsgiving)4. Sawm (Fasting)5. Hajj (Pilgrimage)Therefore, the second pillar is Salat, which is the obligatory daily prayer.Answer:Salat