Question

Aryan invasions seasonal floods earthquakes Rivers changing courses and a decline in trade were all possible factors that led to the fall of what civilization

Answer 1

There are only 4 reasons that the Indus River Valley may have ended but here they are. 
1.Aryans might have invaded 
2.Drought 
3.Indus River changed courses 
4.Too much flooding and destroyed crops 
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Well your wrong. How can there be a drought and excessive flooding? 
The four reasons are: 
1.) Aryan invasions 
2.) Decreases in trade 
3.) Recurring floods 
4.) Earthquakes and tectonic uplifts
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Actually, it is possible to have drought and flooding, just not at the same time, but that does not mean the first list is better.
There is a link below to an article people can read to discover the latest official version of how the Harappan disappeared.

Answer 2

The correct answer is the Indus Valley civilization.

Aryan invasions, seasonal floods, earthquakes, rivers changing courses, and decline in trade, were all possible factors that led to the fall of the Indus Valley civilization.

The Indus Valley civilization was settled in a risky geographic area that was exposed to earthquakes, river floods, heavy rain, and the changing course of the Indus River. Some natural disasters destroyed their cities, impeding trade with other civilizations. Although Harappan cities were considered modern by the time, they probably succumbed to natural forces and invasions

The other options of the question were a) Mesopotamia, c) Mycenaean, and d) Egyptian.