"which sequence of organisms represents a food chain within this food web?
(1)tadpoles → algae → daphnia → back swimmers
(2)sedges → ants → frogs → kookaburras
(3)algae → daphnia → decayed material → bacteria
(4)dragonflies → sedges → ants →centipedes"

On a spring day, a middle-latitude city (about 40? north latitude) has a surface (sea-level) temperature of 10 ? c. if vertical soundings reveal a nearly constant environmental lapse rate of 6.5 ? c per kilometer and a temperature at the tropopause of –55 ? c, what is the height of the tropopause?