What determines whether a particular cell is able to respond to a hormone?

How are extrusive rocks formed? magma gets trapped inside earth and cools to rock. volcanoes apply force to solid rocks and eject them. magma gets forced to earth’s surface and cools to rock. volcanoes trap lava inside earth, where it cools to rock.

Look at the picture below . what does this picture represent ?

In which situations is the principle of cross-cutting relationship useful in determining relative age?