In the absence of external forces such as mutation or genetic exchange, the third generation of a bacterium will have approximately 75% matching DNA sequences compared to the original parent cell. This is because each generation of bacteria typically undergoes binary fission, where the original DNA is replicated and passed on to offspring.
Here’s a breakdown of the percentages of matching DNA over three generations:
- The original parent cell (0th generation) has 100% of its own DNA.
- The first generation (1st generation) will have 100% matching DNA with the original cell.
- The second generation (2nd generation) will still retain the same DNA sequences as the first generation, also having 100% matching.
- The third generation (3rd generation) will still contain a copy of the DNA that came from the original parent cell.
Therefore, all generations (up to the third) would have 100% matching sequences to the original parent.
So, your answer should be 100%.