What major geographic event happened in the precambrian era? PLEASE HELP

What statistics are to determine the development of a nation?

[fw.02]sinkholes are often formed as a result of the actions of. a.heat on recharge b.pressure on aquifers c.acid in groundwater d.minerals in hot springs

When reading a textbook blank. a) it’s safe to assume that the ingot is not biased b) you should watch for fallacies in information and author bias c) you should fact check everything you read d) it is understood that academic sources are not biased