Studies of conjugation in multiple Hfr strains revealed that the bacterial chromosome was: circular. single stranded. directional. None of the above

circular

Explanation:

Studies of conjugation in multiple Hfr strains revealed that the bacterial chromosome was circular.

Conjugation in bacteria is a process through which genetic materials are directly transferred from one bacterium to another. The process was first discovered by the experimental work of Joshua Lederberg and Edward Tatum in 1946. The donor bacterium first makes a copy of the genetic material by replication and then pass a copy to the recipient bacterium.

It was during the process of conjugation that scientists discovered that the genetic material of the bacteria is a circular chromosome, also known as the F plasmid. The circular chromosome breaks at a particular point and becomes a linear structure before replication and then folds back thereafter. The replicated chromosome is linearly transferred to the recipient cell.

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.