Need asap will mark sully works as a geologist in the southwestern united states. he plans to choose an unstable isotope to find the absolute age of a rock sample. which two aspects must he consider before making his choice? (more than 1) 1. there should be a sufficient amount of the selected isotope in the rock. 2. the isotope should be one that decays at a very fast rate. 3. the isotope must not be found in any neighboring rocks. 4. the half-life of the isotope must be long enough to capture the age of the rock. 5. there should be more than one unstable isotope in the rock.

The correct answers are

1. There should be a sufficient amount of the selected isotope in the rock.

4. The half-life of the isotope must be long enough to capture the age of the rock.

Good luck!

then that particular organisms become extinct.

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.