National Dental Examining Board of Canada (NDEB) Practice Exam

Girls typically experience a growth spurt around the ages of 10-14, while boys experience their growth spurt a few years later, around the ages of 12-16. This accounts for the average difference of 2 years between girls and boys in terms of growth. Options A, C, and D are incorrect as they do not accurately reflect the usual difference between the growth of girls and boys. Additionally, it is important to note that these are just average differences and individual growth patterns can vary.