1. The cell in this demonstration began mitosis with two chromosomes. How many chromosomes did it have at the end of mitosis? 2. Why must a cell make a copy of tis chromosomes before cell division?

3. What structure holds sister chromatids together?

The density would be 1.622

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.