Leading strand during $DNA$ replication is formed

Who used heavy nitrogen $N^{15}$ for proving the semiconservative way of $DNA$ replication?

What is the full form of $SSBP$?

Distinguish between: Leading strand and Lagging strand.

Experiments involving the use of radioactive thymidine to detect the distribution of newly synthesized $DNA$ in the chromosome were performed on which plant?

Select the incorrect option from the following.