does this can be watch by children below 18 years

It has a lot to do with your child's education level and maturity. I could see myself having watched this show when I was 15 or 16 and being completely okay and comfortable with what was going on, I might have learned some things that I didn't really need to learn though. Hence the rating that suggests audiences of 18 and older.

oh i dont think that , because dont have explicite scenes

i think this kind of show is not good for age 18 below. coz its more of matured thing. that only my opinion...