During DNA Replication, the DNA molecule unzips itself so that there are two free strands of DNA. Both of those strands then create new complementary strands of DNA. Thus every subsequent generation of DNA uses one of the parent cell's strand of DNA as a template, which is why DNA replication is said to be semi-conservative. Hope this helped!
This is 21st century .In this time our society as well as all of the world had become advanced and modern.So,in this time if we started to work without any technology then while working we need more manpower and our time will be loss.Science ,technology,engineering and maths play important role in modern world d .It helps in sustain able development and helps any country to be self dependent and makes profit by which Nations will be developed and it helps to win the future.