Folds, wrinkles, etc!
by folding the membrane of an organelle, surface area is optimized while volume remains the same. that is why mitochondria looks folded on the inside when you see pictures of it. the higher the surface area to volume ratio, the more efficient the organelle.
a glacier made of ice can erode a landscape made of rock because there can be water held within the rock that gets frozen, and because water expands when it is frozen the rock breaks apart and the glacier grinds its' way 'downhill' (down a mountain range, a good example of this is the Appalachian mountain range) and carves out a significant amount of material that is below it, as well as the materials frozen inside of the glacier. so glaciers can freeze the rocks, and then scrape away any material that is softer than rock.
The limbs of the organisms are similar because they are formed in similar ways during embryonic development and share similar arrangements.
Miller Urey experiment mimics the environment we had for earth billion of years ago. They put in inorganic molecules and came out with organic molecules. Other scientist thought that they messed up their experiment, but once other scientists recreated and tested. They saw that Miller and Urey were correct. And that helped them see that the origin of life can come from simple cells.