A genetics student was asked to draw the chemical structure of an adenine-and thymine-cont...

A genetics student was asked to draw the chemical structure of an adenine-and thymine-containing dinucleotide derived from DNA. His answer is shown here:

The student made more than six major errors. One of them is circled, numbered 1, and explained. Find five others. Circle them, number them 2 through 6, and briefly explain each in the manner of the example given.