(a) Three effects of rotation of the earth include:
(i) It causes day and night
(ii) It causes the deflection of winds and ocean currents
(iii) It causes the rising and falling of the tides.
(b)(i) Reasons why all areas north of the Arctic cycle have 24 hours of daylight on June 21:
(i) The sun appears to move northwards on June 21
(ii) Daylight increases as one goes towards the north pole.
(iii) The sun never sets at mid-summer (nature of season)
(iv) The earth is inclined to the plane of the ecliptic which causes the variation in length of daylights.
(b)(ii) Reasons why areas within the tropics have more sunshine than areas outside the tropics
(i) The sun is always overhead at the tropics
(ii) It represents the centre of the earth
(iii) It is the region which only experiences equal day and night (equinoxes)
(iv) There is variation in length of day and night towards the poles.