Question

the sun can only ever be directly overhead in the: tropics temperate zone poles boreal zone

Explanation:

The sun is directly overhead (solar noon with \(90^{\circ}\) solar elevation) within the tropics. This is because the Earth's axial tilt (\(\sim 23.5^{\circ}\)) causes the subsolar point (where the sun is directly overhead) to move between the Tropic of Cancer (\(23.5^{\circ}N\)) and the Tropic of Capricorn (\(23.5^{\circ}S\)) over the year. In the temperate zone, the sun never reaches \(90^{\circ}\) elevation. At the poles, the sun has a maximum elevation of \(23.5^{\circ}\) (summer solstice) and is below the horizon for part of the year. The boreal zone (sub - arctic) also does not experience the sun being directly overhead.

Answer:

tropics