Questions

In the early 1950s two scientists, Rosalind Franklin and Maurice Wilkins, studied DNA using x-rays. Franklin produced an x-ray photograph that allowed two other researchers, James Watson and Francis Crick to work out the 3D structure of DNA. The structure of DNA was found to be a double helix.

The Great Depression was a severe worldwide economic depression that took place mostly during the 1930s, beginning in the U.S. The timing of the Great Depression varied across nations; in most countries it started in 1929 and lasted until the late-1930s. It was the longest, deepest, and most widespread depression of the 20th century. In the 21st century, the Great Depression is commonly used as an example of how far the world's economy can decline.

Both 2 and 3 are clearly the diadvantages of circular list

Deleted files are not permanently removed from the hard drive or the computers memory. Before they are permanently removed from the system they are stored in Recycle Bin. Recycle Bin is a folder or directory where deleted items are temporarily stored. It is also called as trash.