It would help if you had copied the question correctly.
summarize comparing the characteristics and innovations in 200-300 words. Provide two representative examples of arhitecture for each Greek and Roman cultures.
Your text is the best source of this information.
You will also find a wealth of information in these sites.
Roman Structural revolution
Concrete = cement plus an aggregate. An aggregate is a binding agent such as sand or gravel that is added to cement to form concrete.
Not a Roman invention
Composed of lime, sand, and water
Romans added a local volcanic ash called pozzolana
Produced a cement of exceptional strength
Composed of stones, gravel, building debris, chips from stone quarries
Thus: Roman cement + Roman aggregate = Roman concrete
Far superior in strength to any earlier versions
Advantages of concrete over natural stone
No need to quarry it or transport it
Could be mixed on site
Could be cast into almost any shape
Disadvantage of concrete compared to natural stone
Not inherently weather resistant or aesthetically pleasing
Entasis: a column that curves outward in the middle of the shaft
The column shaft gets narrower as it approaches the capital and the base.
It is found on both smooth and fluted columns, and was a major feature of Greek architecture. Roman architecture also used entasis.
Why it exists: it is an optical correction or refinement that helps a column appear straight (and therefore sturdy). Otherwise columns might appear as though they wanted to collapse inward.