The relative ages of Layers D, S, K, N, and G can be determined by using which principle? (please help its a science question)

Relative age is the age of a rock layer (or the fossils it contains) compared to other layers. It can be determined by looking at the position of rock layers. Absolute age is the numeric age of a layer of rocks or fossils. Absolute age can be determined by using radiometric dating.

I hope this helps! I gave it my best shot :D

If you look at a picture of a cell membrane (http://apbiomaedahs.weebly.com/uploads/1/8/4/0/18405139/593679327_orig.jpg?510)
you'll see that there are 2 layers (bi- means 2) of the yellow things (the round heads are hydrophilic and the tails are hydrophobic and face each other), hence the name lipid bilayer