Why was the Yellow River important for ancient Chinese dynasties?

Without the protection provided by the river, dynasties were open to invasion.

Without the food grown in the river valley, dynasties could not remain in power.

Without the transportation provided by the river, dynasties could not reach the sea.

Without the large population in the river valley, dynasties were unable to raise armies.
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The y-value if a data point corresponding to x1

This graph represents four ecosystems. each ecosystem has a different number of species, adding to its biodiversity. different colors represent different species. which statements correctly summarize the data depicted by the graph? 1. ecosystem d has more biodiversity than ecosystem c. 2. ecosystem b has more biodiversity than all the other ecosystems. 3. ecosystem a has more biodiversity than ecosystem b but less biodiversity than ecosystem c. 4. ecosystem b has more biodiversity than ecosystems c and d but less biodiversity than ecosystem a. 5. ecosystem a has more biodiversity than ecosystem c but less biodiversity than ecosystem b.

Match each fossil with the layer where it’ll be present based on those conditions.