<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>
Atoms are grouped together by their number of valence electrons
Answer:
Fossil fuels
explanation: Coal is one type of fossil fuel. This is a nonrenewable energy source whose extraction often damages the environment. Fossil fuels are made from decomposing plants and animals. These fuels are found in the Earth's crust and contain carbon and hydrogen, which can be burned for energy
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Number 3. The cell membrane forms the outer boundary of the cell
