Isochron Question # 4

Isochron Diagrams

4.	How could you tell an older rock from a younger rock just by looking at their isochrons?
	The older rock would have more points on its isochron.
	The younger rock isochron would have a steeper slope.
	The older rock isochron would have a negative slope.
	The older rock isochron would have a steeper slope.
	There is no way to tell which is older.