I'll add some bits of explanation to the correct answers provided by the other respondent.
1. To reduce the amount in blocks or sizable amounts - decimate
The word "decimate" comes from Latin, with the literal meaning, "taken as a tenth." If a group of soldiers became mutinous, Rome had the policy of executing a tenth of the men in that legion as a warning of what would be done to those who didn't remain loyal.
2. food and drink; necessary foods in order to stay alive - sustenance
"Sustenance" is a noun related to the verb "sustain." Food and drink are what are needed to sustain life, thus "sustenance."
3. Settlement that that relocated due to lack of resources and sustenance - Sinagua Indian tribe
The Sinagua people lived in areas now part of the state of Arizona. The name "Sinagua" was given to the tribe by archaeologist Harold Colton. The name was formed from the Spanish word "sin" (without) and "agua" (water), because the region they inhabited had so little water.
4. Civilization that may have fallen due to a lack of goals - Rome
There are multiple theories and whole books written on why the Roman empire fell. I'll not try to get into all those theories here!
5. Grew due to the goals of increasing its international trade - New York City.
New York City remains a center of international trade. The presence of One World Trade Center in New York is a testimony to that role of the city. One World Trade Center is the rebuilt establishment of the World Trade Center which was attacked and destroyed by terrorists on 9/11/2001.
