The ratio of parent to daughter isotopes in a radioactive decay process is 0.40. How many half-lives have elapsed since the material was 100% parent atoms? A Between 2 and 3
B More than 3
C Between 1 and 2
D Less than 1

the diploid number of chromosomes is sometimes represented by the symbol 2n. for the fruit fly, the diploid number is 8, which can be written as 2n = 8, where n represents twice the number of chromosomes in a sperm or egg cell.