Topic test review
what are currents?

An ocean current is any more or less permanent or continuous, directed movement of ocean water that flows in one of the Earth's oceans. The currents are generated from the forces acting upon the water like the earth's rotation, the wind, the temperature and salinity differences and the gravitation of the moon.

A single replacement reaction, sometimes called a single displacement reaction, is a reaction in which one element is substituted for another element in a compound. The starting materials are always pure elements, such as a pure zinc metal or hydrogen gas, plus an aqueous compound.

Explanation:

The three types of chemical reactions are synthesis, decomposition, and replacement. Replacement – when one element replaces another element in a compound, or if two elements in different compounds trade places, the reaction is called a replacement.