Fill in the blanks choosing the correct option from the bracket:
i. Pressure belts oscillates between ______ parallels.
(5° to 7°, 10° to 20°, 80° and 90°, 25° to 30°)
ii. The instrument used to measure air pressure is ______ .
(barometer, thermometer, hygrometer, seismometer)
iii. In both the polar regions, the temperature is below ________ throughout the year.
(5°C, 0°C, 7°C, 6°C)
iv. The line that joins the places of equal pressure on the map is called an _______.
(isotherm, isohytes, millibars, isobar)