MOD Non-Verbal, Quantitative & Analytical

A five-year-old child says the water poured into a tall, thin glass is 'more' than the same water in a short, wide glass. According to Piaget, this child is in the stage called:

What is the next number in the series: 3, 5, 8, 13, 20, 31, ?

A dispute arises between two countries over a military buildup along their shared border, and the matter is brought before the UN body that carries the main responsibility for maintaining international peace and security. Which body is this?