Riddle No 15: a Visible "d"

29. When the "d" is visible, it can grow to be many things.
The answer - a seed (=see + "d")

30. Although I never learned to read or write, my book is one of the most famous in the world. At the beginning, my views were not accepted by most of my family and I was forced to exile. Years later, I returned and became my city leader. Who am I?

The answer - the prophet Muhammad.