I'm pretty sure the answer would be C, can be done.
<span>When a social group is isolated for a long time, customs tend to ossify - making change difficult.
The verb <em>to ossify </em>in its primary meaning refers to bones hardening, to stiffening, fossilizing, solidifying, hardening. Its metaphorical meaning would be to stagnate, to cause difficulties, to cease developing, which is the meaning in the sentence above. </span>
The website citations are formatted correctly are:
Greene, Tom. Home Composting. Hanover Growers Guild, 15 March 2010.
Web. 22 April 2011.
Lawson, Jennifer. Put Down the Pesticides. Organic Advocates, 31 May
2013. Web. 3 January 2014.
Answer:
Here you go:
Distinct dynasties built different courses of boundary walls. They reach in total from Liaodong in the east to Lop Lake in the west, from the present-day Sino-Russian border in the north to the Tao River in the south, along an arc that roughly delineates the Mongolian steppe's boundary. The Great Wall's protective system is now widely regarded as one of history's most spectacular architectural marvels.
Hope this helps.
