Mountains because the tectonic plates are colliding and pushed up against each other.
Doldrum is the region of very calm and little or no wind on either side of the equator. Doldrums which is also called convergence zone is an equatorial region of the Atlantic ocean which has sudden storms and light unppredictable winds. In addition doldrum is abelt around the earth near the equator where the sailing ships sometimes get stuck on windless water.
<u>Answer:</u>
<em>Rigel and Betelgeuse </em>
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<u>Explanation:</u>
Rigel and Betelgeuse are counted in the brightest stars of the galaxy.
They form a pair in the Orion constellation.
The Rigel star is situated near the Equator. This star is invisible in the region around and above of latitude 82°N and can be seen from any part of the world. It is a blue white giant star. This makes Rigel helpful in navigation.
Betelgeuse is a red giant star which is visible from naked eye. It has the same diameter as that of Jupiter.
D. Islands used for agriculture
