DNA analysis is the process in which genetic sequences are studied. It is used by law enforcement and medical personnel to identify a particular person or species, and even specific cancers and diseases. At one point the analysis process was very limited.
To round off to the nearest tenth, means to keep one decimal digit. (To round off to the nearest hundredth would mean to keep two digits; to the nearest thousandth, three; and so on. Now, the digit in the second decimal place is 5. Therefore add 1 to the previous digit 2.
That means you round to the nearest single digit. (Round to get rid of the decimal.) Example: 435.2 metre would round to 435. 435.6 metre would round to 436. If they wanted you to round to the nearest ten for example, it would say round to the nearest ten metres. They mean to round it off to the nearest bus station.