La niña refers to than normal ocean temperatures in the ocean.

La Niña refers to COLDER than normal ocean temperatures in the PACIFIC Ocean.

La Niña is a climatic phenomenon that is part of a natural-global climate cycle known as El Niño-Southern Oscillation (ENSO). This global cycle has two extremes: a warm phase known as El Niño and a cold phase, precisely known as La Niña. When there is a regime of strong trade winds from the west, the equatorial temperatures decrease and the cold phase or La Niña begins. When the intensity of the trade winds decreases, the surface temperatures of the sea increase and the warm phase begins, El Niño.

Either of these conditions expands and persists over tropical regions for several months and causes marked changes in global temperatures, and especially in global rainfall regimes. These changes occur alternately in periods that vary averaged from five to seven years.

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

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