I believe the answer would be Crossing Over.
Hope this helps.
Answer:
D is incorrect. Took the quiz. The most acceptable answer is either A or C
1.Fish gills are organs that allow fish to breathe underwater. Most fish exchange gases like oxygen and carbon dioxide using gills either on side of the pharynx.
2.Gills are branching organs located on the side of fish heads that have many, many small blood vessels called capillaries.
3.The colour is red
4. A Gill filaments project from each arc between the dorsal upper and ventral lower surfaces of the filaments.
Fossils can be found in the Earth's crust.
The crust is the thinnest layer of the Earth. The fossils are most probably be found in this layer because it is the outermost layer. Also, the deeper the layer of the Earth, the higher the temperature that it has, and it probably cannot preserve the fossil.