Why did both attempts to settle Roanoke fail?

When a dam is built in a hot, dry area, creating a lake or reservoir aboved the dam, how does the evaporation from that reservoir affect the environment ?

In a 2010 article “fact check: eastern u.s. earthquake risk” by chris mould, the author provides as evidence the following statement by the united states geological survey: “although earthquakes may be less frequent in the eastern u.s., … urban areas in the east could face bigger losses because the shaking would affect much larger areas than similar quakes in the west. in addition, most homes and buildings in the east are not designed to withstand earthquakes.”this statement directly relates to which of the following concepts? a. vulnerabilityb. hazardc. riskd. severity

What are the similarities and differences in the way geologists and biologists approximate the age of the earth? justify your response in two or more complete sentences.