The answer is; Warm water moves to the east instead of to the west
Normally, when the waters in the Pacific warm up, the prevailing winds that blow from east to west drag the warm surface currents westwards and upwelling of cold currents occur at the west coast of South America. However, in El Nino, the Pacific ocean waters heat more than usual. The prevailing winds weaken and begin to blow predominantly towards the east. The warm currents are therefore dragged to the east and cause torrential rains in Western coast South Americas.
It is definitely not a primary source: this would be a book itself.
Now, is it a tertiary source? I don't think so: the author of the review should have read the book and should only be referring to this book in the review.
I think it's a secondary source.
Answer:
The correct answer is - option A. aldosterone.
Explanation:
Aldosterone is secreted by the Zona glomerulosa of the adrenal cortex of the adrenal gland. It is mineralocorticoid which is a steroid hormone that signals the kidney to prevent sodium ion and water in case of low blood pressure and volume in vessels. To save the water and ion of salts it promotes the reabsorption and leads to low urine output.
On another hand, ANP or atrial natriuretic peptide which release from the heart and enhances the urine output in response to high blood volume and pressure as it ceases the release of the Aldosterone.
Thus, the correct answer is - option A.
