What are the advantages of a multiple column grid? 

A multiple column grid is helpful because the designer can put multiple elements in the spread. The multiple column grid gives the designer a space to put everything that they need onto the spread. It also allows you to have easy hierarchy since the grids make placing things and seeing the size of the simple.  

How many characters is optimal for a line length? Words per line?

You should have about 50-60 characters per line. This means about 9-12 words. 

Why is the baseline grid used in design?

A baseline grid is used to help create hierarchy in a design. It also creates a common place to put your objects so that the document has unity.  

What are reasons to set type justified? ragged (unjustified)?

You should set type to be justified if you want a clean shape in your copy. You should use ragged type if you want the type to flow naturally. Both should be used according to the typeface and how the spacing will look when you do it. 

What is a typographic river?

A typographic river is when the spaces in the text align and create a blank space which line down the body of text. 

What does clothesline, hang-line or flow line mean?

A clothesline is the space where images, captions, or headers are placed. 

What is type color/texture mean?

Type color is the color of the text. Tighter bodies of text have a higher contrast compared to text bodies that are spread out and have a lower contrast. Type Texture is from the combination of different typefaces in one document.

How does x-height effect type color?

X-height is effected by type color because the larger the x-height, the more the colors stand out. This is because they are more legible. 

What are some ways to indicate a new paragraph. Are there any rules?

You can indicate a new paragraph by indenting, outdenting, double spacing, with colors, with a new typeface, or with size. Either indent or double space, not either.