Sedimentary: a rock that has formed from sediment deposited by water or air.
Example: breccia, conglomerate, sandstone and shale.
Igneous: a rock having solidified from lava or magma.
Example: diorite, gabbro, granite and pegmatite.
Metamorphic: a rock that has undergone transformation by heat, pressure, or other natural agencies.
Example: gneiss, phyllite, schist and slate.
Stratification: a system or formation of layers, classes, or categories.
Studying the amount of layers in a rock can determine their age. It works this way because overtime the rock will gain more the longer its around. They can also determine the place the rock was in the way the layers are on the rock and the other characteristics of the rocks layers. If a rock has plenty of layers, you can figure that the rock has been around for a long time. (The age of the rock is an estimate, not exact)
Sedimentary rocks top layers are the youngest. The cause of large horizontal peices creating more layers can be because of earthquakes and also erosion. As a specific place goes through the erosion process it can cause the place underneath the larger peices to give out, causing them to fall. Older layers may possibly be on top as well because of the heat or magma from under the earths crust causing more layers to be packed on the bottom of the rocks.
Living organisims have changed/created landforms in a lot of ways. For instance, Oil Deposits comes from the remnants of the inside of Phytoplankton. Also, Coal is made of Ancient Bog plants. Limestone deposits come from the composed shells of marine protists. Lastly, Coral islands have been formed by the tiny creatures called coral polyps.