Answer:
1. Continental-continental convergence are both <em>continental crust</em> plates.
2. Buoyancy basically means these plates are light float on top of the Asthenosphere.
Explanation:
1. To go a little more into detail, this type of convergence ocurrs when two plates made of continental crust (not oceanic) collide. In the case of ocean-continent convergence, the denser oceanic crust sinks underneath the lighter continental crust.
In this scenario, we have two plates, neither of which want to sink, so instead of going down they just crumple and fold and keep colliding. This collision creates very high mountain ranges such as the Himalaya and usually doesn't contain any volcanic activity because no magma is capable of penetrating through so much crustal material.
2. As for why continental crust is buoyant and doesn't sink has much to do with its composition. Continental crust is made mostly of silicate material. This is very different from oceanic crust which is made of basaltic rocks and is therefore heavier. The term buoyancy refers to the 'floating action' of the continental crust on top of the uppermost mantle.
<span>C) ships could then take advantage of the currents to speed up travel </span>
The correct answer is - from solar nebula.
The Earth and the other planets in the Solar System are thought to have formed from solar nebula. This solar nebula is believed to have been a left over from the Sun's formation, being consisted of gas and dust in a disc-shape. The material in this disc-shaped gas and dust started to merge gradually, thus little by little forming bigger and bigger objects, and as the objects were getting bigger they had bigger gravitational pull so more and more material was attracted toward them. Because of the very big gravitational pull of the Sun these objects were not able to wander into the space but were instead kept close to the Sun. Because of the orbiting around the Sun, they all started to take a rounded shape. Some planets as the Earth, Venus, Mars, and Mercury became terrestrial planets, while the likes of Jupiter, Saturn, Uranus, and Neptune became gas giants.
