Answer :
The correct pair of statements among the options provided is:
Eclogite is high-grade; gneiss is ultra-high grade.
1. High-grade metamorphic rocks are typically formed deep inside Earth, not near the surface. This statement is false.
2. Gneiss is a high-grade metamorphic rock, while eclogite is an ultra-high-grade metamorphic rock. This statement is true.
3. Eclogite is indeed a high-grade metamorphic rock, while gneiss is classified as ultra-high grade. This statement is accurate.
4. Eclogite can be formed from basaltic rock undergoing high-pressure and high-temperature conditions, transitioning into a high-grade rock. Gneiss, on the other hand, is typically formed from shale or granite, indicating it can be transformed into a high-grade rock like eclogite, not the other way around.
Therefore, the correct pair of statements is:
Eclogite is high-grade; gneiss is ultra-high grade.
