Atoms of A decay to atoms of B with a half-life of 200,000 years. If there are 20,000 atoms of A to begin with, how long will it take for there to be 2,500 atoms of A?

The correct answer is: 600,000 years

Explanation:

Half-life is the time which is essential or required to decrease a specific substance to half of its initial amount of the substance. So, if a substance has a half-life of 200,000 years then it means it takes 200,000 years to decrease or change into a new substance and remain half of its initial quantity.

half-life              amount

     0                  20000

     1                    10000          

     2                    5000

     3                     2500

total half-life = 3 to 2500 atoms of A

so, the time will be = 3 * 200,000 years

 = 6000000

i would go with b

cytokinesis occurs after telophase so that eliminates d

and the entire reason for cytokinesis is for cellular reproduction

i think that d. wind is the answer.   i missed the question when i answered a. currents.