Watson and Crick observed that the two strands of DNA are anti-parallel and complementary to each other with respect to their base sequences. This type of arrangement in DNA molecule led to the hypothesis that DNA replication is semi-conservative. It means that the double stranded DNA molecule separates and then, each of the separated strand acts as a template for the synthesis of a new complementary strand. As a result, each daughter DNA molecule would have one parental strand and a newly synthesized daughter strand.
Since only one parental strand is conserved in each daughter molecule, it is known as semi-conservative mode of replication.
Aditya should clear his concepts because the semiconservative replication model was hypothesized first by Watson and Crick and later proved by Messelson and Stahl ok brooooooo
This experiment was of melson and stahl and not of watson and crick bro