without external forces, the third generation of a baterium and the original parent cell will have approximately ___ matching DNA sequences

The third generation of a bacterium and the original parent cell will have approximately 100% matching DNA sequences. This is because in the absence of external forces such as mutations or genetic recombination, the DNA in bacteria is replicated and passed on to the next generation through a process called binary fission. As a result, the daughter cells produced in each generation will have exactly the same DNA sequence as the parent cell.