Which describes pumice and obsidian?

A.

Pumice is a coarse-grained extrusive igneous rock, while obsidian is a fine-grained intrusive igneous rock.

B.

Both pumice and obsidian are fine-grained extrusive igneous rocks.

C.

Pumice is a fine-grained intrusive igneous rock, while obsidian is a coarse-grained extrusive igneous rock.

D.

Both pumice and obsidian are coarse-grained intrusive igneous rocks.

Question

Which describes pumice and obsidian? 	
	
 
A.
	

Pumice is a coarse-grained extrusive igneous rock, while obsidian is a fine-grained intrusive igneous rock.
	
 
B.
	

Both pumice and obsidian are fine-grained extrusive igneous rocks.
	
 
C.
	

Pumice is a fine-grained intrusive igneous rock, while obsidian is a coarse-grained extrusive igneous rock.
	
 
D.
	

Both pumice and obsidian are coarse-grained intrusive igneous rocks.

anonymous · Answer

plz help

mathmath333 · Answer

i m clueless here , someone in geography section might help

mathmath333 · Answer

answer shoyld be B or C as

obsidian is extrusive igneous rock

anonymous · Answer

where is it

anonymous · Answer

good enough

mathmath333 · Answer

hey its 
B Both pumice and obsidian are fine-grained extrusive igneous rocks.

mathmath333 · Answer

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock.
Pumice is composed of highly microvesicular glass pyroclastic with very thin, translucent bubble walls of extrusive igneous rock

anonymous · Answer

oh ok thx

anonymous · Answer

ok cool i am obsidion but i wasnt sure about pumice XD

mathmath333 · Answer

http://en.wikipedia.org/wiki/Obsidian http://en.wikipedia.org/wiki/Pumice

mathmath333 · Answer

geography is still an very intersting sub , since childhood for me