Ancient egyptian astronomers studied the stars to

a)predict the flooding of the nile river

b)appoint the next pharaoh

c)create new medicines from plants

d)create a new writing system

Option A.

Explanation:

Predict the flooding of the Nile River, is the right answer.

The beginning of Astronomy in Egypt may be dated back to the prehistoric times or easy to say to the Pre-dynastic Period. The people of Egypt since the Dynastic period was using the Egyptian calendar. However during the course of time,  astronomers starting observing stars to determine annual flooding in the river Nile.

ayatollah khomeini can best be described as the leader who declared iran to be an islamic republic.