Thinking critically potassium-40 decays to
the noble gas argon-40. what problems
might arise when these radioactive iso-
topes are used for age dating?

The radioactive isotopes of Potassium-40 generally observed to decay to argon-40 and calcium 40, also called daughter isotopes. The problem arises with the calcium 40 radioisotopes which cannot be used for age determination due to its excessive presence.

Explanation:

The radioactive isotopes Potassium 40 decays to argon 40 helps in determining age of fossils and rocks mainly due to the fact that extreme heat causes radioactive potassium to decay to noble argon-40 gas. The rate of decay is attributed to its half life period which in turns help in finding the relative age of fossils or rocks. But, problem occurs when it decays to calcium 40, as because calcium forms large part of many minerals including bone.

the pic attached shows the stages of mitosis. hope it !

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.