MIPS: "lw" instruction path

Question

From lecture notes:

from what I understand, doesn't the black dots indicate the binary bits is being copied to both paths moving forward?

For example, instruction bits I[20-16] should be going into the Read register 2 and Write register. It's just that in the end, the Read data 2 is not being used due to the MUX selecting 1.

Did my prof choose not to draw the red lines going to the Read register 2 path just to emphasize on the most significant path? Or does the black dot before Read register 2 have the ability to close off irrelevant data path?

Answer 1

Your professor is only highlighting the paths that affect the result. This is normal -- if every path that contained data were highlighted, everything would be red.