Spanish language Q&A Forum

In this question from a quiz:

"El presidente ________ Gobierno tiene su residencia oficial en el Palacio de la Moncloa, en Madrid"

I was told that it should be del. However, in the lesson it says not to use contractions prior to proper nouns. Is this not a proper noun, despite the fact it is capitalized?

Is there any problem with adding "se" to the verb "reír" here? 

Why do we say "ciento por ciento"? Ciento is more than one hundred so shouldn't it only be cien por ciento and cien por cien?

I see oenegés as the original transcript - but wouldn't it be O.N.G. like the acronym in English?

"quien había fallecido"

Just wondering, why is it que in the first example and quien in the second?

why is tenido sometimes with an accent on the nand sometimes without. The correct answer for this question was with an accent wheras another question using tenido was without. My collins dictionary says without. 

I thought that porque explained the cause of something whereas como presented a fact that the listener needed to know to understand what followed (but was not the cause).   It I’m not sure if that rule works with the examples here?  Am I missing something?

The kwiziq page "Ser vs Estar in Spanish: Using ser in Spanish (not estar) to talk about time, days, dates and seasons" (Ser vs Estar in Spanish: Using ser in Spanish (not estar) to talk about time, days, dates and seasons) says

   Hoy es lunes.  =  Today is Monday.  ("Today" is singular.)

but

   Son las tres de la tarde.  =  It's three o'clock in the afternoon.  ("It" is plural.)

Why are these different?