The correct matching options are:-
2. Pharyngeal gill slits- B. feature that arose in reptiles and helped vertebrates to colonize land.
The reptiles required lungs for breathing air to survive on land instead of absorption of air through skin in amphibians. Pharyngeal gill slits are openings present between the pharynx and outside.
3.Notochord- C.flexible structure that supports the nerve cord and led to the evolution of the backbone.
The notochord has its function in providing skeletal support and acts as a point of attachment for the muscles.
4. endoskeleton- A.) internal support system that allowed for large, heavy bodies.
Endoskeleton is the internal support of the body and also helps in movement of muscles through levers.
6. amniotic egg- D. structure that develops within the mesoderm and is allowed for more complex internal organ formation.
The amniotic egg is produced by several reptiles, birds and egg laying animals in which the egg develops within the amnion or amniotic fluid and the egg is covered with a calcium based shell.