Why an isotonic solution is used to treat dehydration?

Isotonic IV solutions restore fluid volume because they fill the tissues and maintain fluid volume more effectively than hypertonic or hypotonic solutions

For large volume replacement, isotonic or nearly isotonic solutions are used. Sodium chloride (0.9%) solution or Ringer's solution (not lactated Ringer's) is a good base solution. Potassium chloride should be added to either solution at a rate of 20 to 40 mEq/L.

the index of refraction of the second medium is higher. i just took the test trust me !

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.