In which area does clean drinking water present the biggest problem?

Impressions of tropical swamp plants were observed on rocks in polar regions. the impressions were dark black imprints, which means the fossils are examples of ( 1 ) the fossils tell us that polar regions ( 2 ) ( 1 ) a. carbonization b. mineralization c. trace fossils ( 2 ) a. had tropical plants that can grow in ice b. might have had a diffierent climate in the past c. will have abundent vegitation

The coco river is a natural border between nicaragua and which other country

Simple astronomical telescope the objective lens has a focal length of 75 cm and that of a piece of 5cm of the lenses are 18 cm apart when will be final image of a distant object before