Questions: If magmas do not have excess heat, the heat needed for melting must come from the crystallization of primary minerals in the magma. True

The statement is False.

Explanation:

1. Magmas can acquire the heat needed for melting through various processes, not solely from the crystallization of primary minerals.
2. Crystallization of minerals in magma is an exothermic process, meaning it releases heat, but this is not the only source of heat for melting.
3. Other sources of heat for melting include the geothermal gradient, heat from the mantle, and heat from tectonic processes such as subduction or mantle plumes.
4. Therefore, the statement that the heat needed for melting must come exclusively from the crystallization of primary minerals is incorrect.