Answer:
Immunity to Small Pox
Explanation:
Over the years, Europeans had built up an immunity to smallpox because many had contracted the disease and still survived. As the population grew children were born with some immunity to the disease. When the Europeans arrived in the Americas, and smallpox spread around the native peoples, the Europeans did not contract the disease because they were immune. However, since the natives were not immune, they slowly died of due just to the disease as well as some parts of the war between the europeans.
Answer:
WATER REABSORPTION IN THE COLLECTING TUBULE OF TE KIDNEY
Explanation:
Antidiuretic hormone synthesized by the neurons in the hypothalamus and the posterior pituitary allows for the reabsorption of water from the collecting ducts of the kidneys back into the circulation.
This therefore reduces the amount of water in the urine causing the formation of concentrated urine and reduced volume of urine.
It causes the increased reabsorption of sodium in the ascending loop of Henle adding to the counter-current mechanism which aids the further reabsorption of water from the distal tubules and collecting ducts.
It also allows the constriction of arteries thereby reducing arterial blood pressure.