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.
One common rounding task is to round a number to the nearest whole number (sometimes, this will be explained as rounding the number to the ones place). In this case, use the same rounding technique as before. In other words, start at the ones place, then look at the number to the right.