Final answer:
The double helix structure of DNA cannot be directly seen. Scientists have used techniques such as X-ray crystallography and electron microscopy to study and understand the structure of DNA.
Step-by-step explanation:
The double helix structure of DNA cannot be directly seen because it is at a microscopic level. However, scientists have used various techniques to study and understand the structure of DNA.
One of the techniques involved X-ray crystallography, which allowed scientists like James Watson and Francis Crick to make accurate models of DNA. They used the data from Rosalind Franklin's X-ray studies to deduce the double helix structure of DNA.
Another technique used to visualize the structure of DNA is electron microscopy, which provides detailed images of molecules at an atomic scale. With the help of these techniques, scientists have been able to confirm the double helix structure of DNA and its importance in genetic information storage and replication.