Cataracts make the lens opaque. Oldest lens fibers are in the interior of the lens. Oldest keratinocytes are at the surface of the epidermis. The trunococonal septum is the tissue that develops to separate the aortic vs. pulmonary vessels. These are far fetched, but apply what you know about inductive relationships and competence.
Umbilical arteries deliver to placenta for same purpose.
They will be retained as gill arch vessels, which acquire O 2 from water passes through gill slits. It will form muscles expected of the A region It will form muscles expected of the B region. It will form a vertebral bone typical of the A region. It will form structures intermediate in form between A and B regions. It will be incompetent to respond to inductive signals in its new locale.