Which property of argon makes it useful for potassium-argon dating? It decays into potassium. It is an unstable element. It remains trapped in rock. It is useful only for dating newer rock.

Iassume the answer is 75 feet. inwards to outwards rather than outwards to inwards. probably be 75.hachures are stokes drawn in direction of the steepest slope. a series of short parallel lines drawn on a map to indicate topographic relief. it is actually called hachures on contour lines. the small marks in the center of the feature are called hachures.observe the picture attached