Wht are the definitions of these words. Communication systems

Import dependency

Opencast mine

Hinterland

Which topic would a meteorologist most likely research? -meteors in space -marine ecosystems -atmospheric conditions -the runoff of stream systems

How far is a geographic second? a.) around 100 feet b.) around 1,000 feet c.) around 5,000 feet d.) none of the above

Can you give an explanation of what medc and ledc are.