Two things affect the barometer's reading, the high or low air pressure caused by weather systems, and the air pressure caused by the station's elevation, or how high it is above sea level.
(Two things; affect; the barometer's reading) (the high or low air pressure; caused; by weather systems) (the air pressure; caused; by the station's elevation) (it; is; L:above sea level)
Two things the high or low air pressure the air pressure it
affect caused caused is
the barometer's reading
by weather systems
by the station's elevation
L:above sea level