After three half- lives, a sample contains 10 grams of parent isotopes. how many grams of the parent isotope were present to start?

its not for its for earth/space science

Initial amount of parent isotope present in the sample was 80 grams.

Explanation: Initial amount was= 80 grams

The sample undergone radioactive decay and after first half-life, it has= 40 grams (half of initial amount)

after second half-life, it has= 20 grams

And after third half-life, it has= 10 grams

Thus, the sample at present has 10 grams and initially had 80 grams of the parent isotope materials.

the form of energy changes and the total energy increases0l

c.more precipitation,but only when emission levels.