Final answer:
The African Plate and South American Plate, as well as the North American and Eurasian Plates, are examples of divergent plate boundaries where the tectonic plates are moving away from each other. This movement can form new crust, typically at mid-ocean ridges or rift valleys.
Step-by-step explanation:
Among the options provided, the following are divergent plate boundaries:
- C. African Plate and South American Plate
- D. North American and Eurasian Plate
Divergent boundaries are places where tectonic plates are moving away from each other. This can occur within continental or oceanic plates leading to the creation of new crust. As for option A, the boundary between the Nazca Plate and the South American Plate is actually a convergent boundary, where the Nazca Plate is subducting beneath the South American Plate, leading to the uplift of the Andes. Option B, the boundary between the Pacific Plate and the Eurasian Plate, includes both convergent and transform boundaries, not purely divergent ones.
The process at a divergent boundary usually involves the upwelling of material from the mantle as the plates move apart, which then solidifies to create new, oceanic crust. These plate boundaries can be observed at the mid-ocean ridges, like the Mid-Atlantic Ridge between the African and South American plates, and the ridge system that extends into the Arctic Ocean between the North American and Eurasian plates. They are marked by shallow earthquakes and volcanic activity. Also, divergent plate boundaries can indeed form on land, leading to the formation of rift valleys which can eventually become shallow, narrow seas.