Dear 863211,
Thank you very much for your helpful information.
As mentioned in the "Indruction For I-485"that I-485 is used by a person who is in the US to apply for adjusting permant resident status, if I chose the opertion 1 (submitting the I-485 of my kid studying in Canada tegether with other family member's I-485), the kid studying in Canada will need to be in the US when the application is submitted.
In your response, it will not be necessary for the kid to be in the US at the time of I-485 submission. Could you please provide an explanation?
Thanks a lot!