It messes up the cellular system and may mix with others
The statement is once a year for women over 40 as they're more likely to develop breast cancer. Also it's once a year for all women over 18 with a family history of breast cancer as it is very rare to develop breast cancer as a child.
Percentile Score is the score based on the relative performance of candidates who have appeared for the exam. To calculate a percentile score, the marks secured are converted into a scale ranging from 100 to 0 for each session of examinees.