Perl -- difference between system call and `

Call perl file in the perl file.

eg: In perla.pl
....
system ("perl", "perlb.pl", "$m", "$n");
`perlc.pl`;

Notes:
system is safer , but can not print the output to standard device, but allow the output to file. It also allow the input parameter to perl file

` is tricky , but allow the output to standard device.