T$1.$ What are some of the differences between an array and a data frame?

T$2.$ In pandas, is a one$-$column DataFrame just a Series? Why or why not?

T$3.$ On pg$.133$ of PDA, the author states:

$$When you are assigning lists or arrays to a column, the value$$s length must match the length of the DataFrame.$$

This is not true if you assign a dict or a Series to a column. Why not?