What was the purpose of observatories? to watch the stars
to study cartography
to chart the progress of ships
to develop tools like the astrolabe

ww1 weapons: tank. tanks were used for the first time in the first world war at the battle of the somme. they were developed to cope with the conditions on the western front. the first tank was called 'little willie' and needed a crew of 3.

c. had saved colonel cresap's family from attack by other native americans.

it required the unanimous approval of the states before the congress could enact any measure.