Which change to the chromosome causes robertsonian translocation? part of the chromosome breaks off, causing missing genes on the chromosome movement of genes on the same chromosome duplication of genes on the same chromosome arms of the chromosome are unproportioned, with extra or missing genetic material

Robertsonian translocation is chromosome translocation involving chromosomes 13, 14, 15, 21 or 22. This occurs when one chromosome becomes attached to another. Please see the image attached to have a better understanding.

 part of the chromosome breaks off, causing missing genes on the chromosome and arms of the chromosome are unproportioned, with extra or missing genetic material.

I hope this helps, Regards.

arms of the chromosome are unproportioned, with extra or missing genetic material

geologic time scale (for gradpoint) =)