The parts labeled in the diagram on the left are:

1. Amniotic cavity - the cavity on the top
2. Ectoderm - blue colored cells
3. Endoderm - yellow colored cells
4. Yolk cavity - the cavity at the bottom

The parts labeled in the diagram on the right are:

1. Ectoderm - blue colored cells
2. Mesoderm - red colored cells in the middle
3. Endoderm - yellow colored cells

A text box in the middle reads, ‘During gastrulation, some cells migrate from the ectoderm and form the mesoderm.’