The INTERSECT operator in compound queries returns only the rows that are common to both SELECT statements, ensuring that no duplicates exist. Therefore, it is essential for the SELECT statements to have the same number of columns with compatible data types. Columns named in each SELECT in the compound query can be different, as the intersection operation does not rely on column names but on the data contained within them. Reversing the order of the intersected tables does not affect the result because the operation is commutative. Hence, the correct answers are the statements indicating that INTERSECT returns rows common to both sides and that columns named in each SELECT can be different.