This law states that in an undisturbed rock sequence, the oldest layers are on the bottom and each successive layer is younger than the one underneath it. "sedimentary layers are deposited in a time sequence, with the oldest on the bottom and the youngest on the top."

Blood will come back to the heart through the veins(smaller veins coming together turn into the inferior vena cava then go to the right atrium).

The main role of dna in the  cell is the long-term storage of information. it is often compared to a blueprint, since it contains the instructions to construct other components of the  cell, such as  proteins  and rna molecules.the main function of rna is to carry information of amino acid sequence from the genes to where  proteins  are assembled on  ribosomes  in the  cytoplasm. mark brainliest, my work is good.