How many of the zeros in the measurement 0.050060 m are significant

The answer is:  " 3 (three) " .

   Note:  Since this value is a measured value,
 there are "5 significant figures" in the number:  " 0.050060 " .


       The following "zeros" within this measured value are "significant figures"— (the ones in "bold text" ;  as follows):

     →      0.050060 .

This would be canberra.