Obsidian is an extrusive rock that is formed when magma from underneath the Earth's crust breaches and becomes lava. Once the lava starts cooling, it solidifies and elements are frozen, giving the rock its glassy appearance.
The answer is B. Water can produce electricity.
In most trees and wildflowers, one root, the taproot, is more prominent than the other fibrous roots. The taproot is usually relatively large in diameter and extends more deeply than the plant's other roots, and often has additional lateral roots.
I believe that would be vitamin A, because vitamin A generally increases with age.
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