Answer:
D. hotter rock rises and cooler rock sinks.
Explanation:
We know that as we move <u>towards Earth's center</u>, the <u>temperature rises</u>. This rise in temperature causes rocks to melt (magma). The high temperature and melting of rocks <u>decrease the density of material </u>which makes it <u>move upward</u>. By <u>moving upward</u>, the molten rock <u>starts turning solid</u> and becomes <u>denser again</u>. Here, it <u>sinks back due to gravity</u>. This upward and downward movement of rocks due to density and temperature makes a convection cell.
PS: The formation of convection cells in Earth's interior is also the reason for plate tectonics.
has tremendous biodiversity and high rates of endemic species: of more than 200,000 known species found on Madagascar, more than 80 percent exist nowhere else. Unique to the island are over 100 kinds of lemurs, over 300 species of frogs, and 33 species of tenrecs, miniature hedgehog-like animals. However, it is one of the most threatened ecosystems on the planet.