Replacement lines are a method developed by Beverton and Holt $(1957)$ for incorporating recruitment into stock assessments. Specifically, replacement lines help us to understand$$

Question $2$ options:

how changes in M $($natural mortality$)$ affect the growth rates of exploited stocks.$$

how growth overfishing can be avoided.

how changes in F $($fishing mortality$)$ affect the recruitment rates of exploited stocks.

all of the above are correct