Why were the Greeks surrounded, attacked from three angles ? What or who
caused this to happen??

answer; i believe that the correct answer is (c) arctic tundra;

in the 1800s, locomotives powered by steam made transportation faster and cheaper. the resulting rapid growth of railroads led to the connection of the atlantic and pacific railroad in oklahoma city in 1897.

in the last years of the century, the improvement of steam-based engines the expansion and growth of railroads. this growth increased when the companies started to build and expand, such as the atlantic and pacific railroad, which connected new mexico with california, and missouri with oklahoma. many of these new networks were built in oklahoma, and these changes transportation henceforward.

to tell the truth it is a mix of the a and d because after the romans argued among themselves outside forces took control however it is mostly d.

question as stated in comment

why did the chinese require the portuguese to pay for goods in gold and silver when trading?

choices

portuguese goods were less valuable than chinese goods.

the chinese already had a surplus of portuguese goods.

the imperial government wanted to stockpile gold and silver.

portuguese and chinese currencies were not exchangeable.

this a history q n in ancient time, theres no money exchange. so ans is portuguese and chinese currencies were not exchangeable.