Consider the Marshall method of mix design for bituminous mix. With the increase in bitumen content, which of the following statements is/are TRUE? 

The line ran _______ the page, right through the centre, and divided the page into two.

Kind : ________ :: Often : Seldom

(By word meaning)

In how many ways can cells in a 3 × 3 grid be shaded, such that each row and each column have exactly one shaded cell? An example of one valid shading is shown.