Key examples of index fossils include several species of , which are an extinct group of marine animals whose hard-shelled bodies had three sections.

Advection fog occurs when warm air blows over a cold surface like snow and since tropical water is warm advection fog rarely forms over it

There are four nitrogenous bases that make up dna. the two pyramidines are thymine and cytosine. the two purines are adenine and guanine. these bases pair in a very specific way. adenine - thymineguanine - cytosine i remember it like this: a tall, good cat.