Sinkholes can for when:
A. <span>Rainwater containing carbon dioxide dissolves underground rock
</span>Water in an underground rock<span> or sediment layer is groundwater. </span>Underground<span> water </span>can<span> also erode and deposit material. </span>Rainwater<span> absorbs </span>carbon dioxide<span> (</span><span>CO2) as it falls. The CO2 groundwater creates landforms by </span>dissolving<span> away </span><span>rock.</span>
Answer:
1
Explanation:
The rest are wrong b/c it helped <em>expand</em> China rather than isolate it, they didn't use ships on the Silk Road, and it brought better communications, etc. between countries.
Answer: i think it russia and north india
Explanation: