<span>Damaged dna is excised by endonuclease.
Three excision repair pathways exist to repair single stranded DNA damage: Nucleotide excision repair (NER), base excision repair (BER), and DNA mismatch repair (MMR).</span>
The oesophagus is the region of the alimentary canal where the food passes without the absorption of nutrients. In oesophagus, we find peristalticmovement which is basically rhythmic contraction and relaxation of the oesophagus in order to facilitate the easy passage for the food to pass from mouth to stomach.
The oesophagus is a muscular tube which measures about 8 inches long.
