ANSWER 1: The Geographical conditions needed to build a successful civilization are: sources of water, land which are appropriate for cultivation, climatic condition to survive. This is necessary because the residents of the civilization will be able to farm food for themselves if not they depend on killing animals. Water is an essential item in order for any living organism to survive which is why a source of water is necessary for drinking purposes at the least. Such successful civilizations were Indus Valley Civilization, Egyptian Civilization etc. Both the civilizations were built around a river which became a source of water for the residents.
ANSWER 2: The geographical conditions which posed the greatest challenge for early civilizations were: Unsuitable climatic condition to live, not enough sources of water and barren or desert land. There are old civilizations which were once a thriving place but still went extinct due to lack of these basic supports. For example, the Khmer Empire of Cambodia is an example of how a civilization can end if there are no proper sources of water. The empire had a vast and well planned structure of waterways and reservoirs though in 15th century, the over-exploitation of nature caused water crisis which eventually led to the collapse. Another example is the Norse Viking settlement of Greenland where the people were forced to leave their land as a mini ice age began and it was not anymore suitable to live.
