The DNA of E.coli is:

Explanation

The DNA of Escherichia coli (E. coli) is double-stranded and circular. Let's explain each option and provide the correct answer with details: Double-stranded and linear (a): This is not the correct answer. E. coli has double-stranded DNA, but its DNA is circular, not linear. Double-stranded and circular (b): This is the correct answer. E. coli, like many prokaryotic organisms, has a double-stranded, circular DNA molecule. This circular DNA is found in the nucleoid region within the bacterial cell. Single-stranded and linear (c): E. coli does not have single-stranded DNA, and its DNA is not linear. Single-stranded DNA is often associated with certain types of viruses and is not a characteristic of the genomic DNA of E. coli. Single-stranded and circular (d): E. coli does not have single-stranded DNA as its genomic DNA. Its DNA is double-stranded and circular. Correct Answer: The DNA of E. coli is "b. Double-stranded and circular." Summary: The DNA of E. coli is double-stranded and arranged in a circular form. This circular, double-stranded DNA molecule is located in the nucleoid region of the bacterial cell and is a key feature of prokaryotic genomes.