Who used xrays to take pictures of DNA

What happens when a magniseum ion ia atracked to a chlrene ion

During an experiment, readings for blood pressure in a persons body were found to be constant . however , when he measured by a different blood pressure cuff , the readings differed by 15 points for each reading. this difference indicates that the results are

Which two criteria must be met before scientist can use radiocarbon dating? explain your answer