Which type of plate boundary do you think is between the South American Plate and African Plate? How are the plates moving in relation to each other?

The type of plate boundary between the South American Plate and the African Plate is a divergent one.

The two plates move apart from each other.

Explanation:

The boundary between the South American Plate and the African Plate is a divergent boundary. The plates moved, and between them, there is an oceanic basin. The plates move on top of the mantle, and magma goes up the divergent areas creating new surfaces when it solidifies. The new surface is called a ridge.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).