Due to gravity, layers of originally form
oa) rock; vertically
ob) rock; at an angle
oc) sediment; vertically
od) sediment; horizontally

Size and shape of continents

Molecules called lipids have long hydrocarbon chains that determine the way they act. they can be fats, oils, or hormones, and even exist in our cell membranes 

Synapse nervous system they process and transmit signals. in a neuron