Could someone help me learn what I'm looking at with (NT scan pic included)

Thank you for all of your guesses, ladies! One more question for you all... I'm really not sure what I'm looking at in these u/s. After looking at seemingly millions of nub shots, hoping to learn the science behind this, I got even more confused. Can someone help me clarify? I have my NT scan here: I was 11w6d (had a trigger shot, so know when ovulation was), but am reading at 12w 4 days... There is a pink arrow and a yellow arrow. Which is the nub? And then, what is the other? And does anyone have any good sites that explain the fork thought? Thank you for all of your help!

Nub is where the pink arrow points and I would say girl even though it is early days yet. Not sure what the yellow arrow points to.

Pink arrow is pointing to a girly nub.  The yellow arrow is pointing to what I beleive is a bit of the cord.

Thank you, ladies! Up until this morning, when I've looked at all the confirmed boy and girl nub shots on this site, I was thinking the yellow arrow was pointing to the nub! Then I started seeing more similarities with the "part" that the pink arrow is pointing to, and I got confused! Thanks for clarifying :) Now I know what I'm looking at!