When did the
civilization end?
(year)

ok, so basically your gonna start with 350 ok. so there's 60 seconds in a minute so that means you he can go up 10 ft per minute. soo, after 3 minutes he should be at 260 ft after three minutes : )

is this question from a book? ?

the lines on a surface map are called isobars. isobars are lines of constant pressure which are measured in units called millibars. the numbers indicate the amount of air pressure, in millibars, that each line represents.