I'm not sure how to classify this question so i'll just put it under biology why would a biologist be interested in sedimentary rocks?

Sedimentary rock is one of the three main rock groups (along with igneous and metamorphic rocks) and is formed in four main ways: by the deposition of the weathered remains of other rocks (known as clastic sedimentary rocks); by the accumulation and the consolidation of sediments; by the deposition of the results of biogenic activity; and by preipation from solution.

The bags should be yellow i believe

It is called the medulla oblongata or people usually call it medulla. it is the lower half of the brain stem continuous with the spinal cord.