Explanation:
The Earth's geologic past is divided into hierarchical time periods. This hierarchy comprises eons, eras, times, epochs, and ages, from largest to smallest. The Cenozoic, Mesozoic, and Paleozoic Periods are the three main divisions of the Phanerozoic.
The genetic code is broken down into a series of codons on the mRNA. Each codon consists of 3 nucleotides which (normally) correspond to a single amino acid (e.g. AUG codes for methionine). I say normally because you can also have a codon indicate a stop codon (so no amino acid will be inserted and instead the polypeptide chain will terminate). This mRNA molecule with its list of codons will instruct a ribosome to synthesize a protein according to this code.
This code is the set of rules - based on the triplet or codon. This triplet code is universal - all organisms use the same codons to specify the placement of each of the 20 amino acids in a protein.
For breaking down lactose
Since the other answer got deleted, i'll just answer it for you.
a sinoatrial node is the main pacemaker that begins each heartbeat located in the junctions of superior vena cava and the right atrium. It signals from the node that spread through the atria and determines the heart rates.
A. Break down sugars to use their energy directly
