North africa/southwest asia
-the region is mainly islamic.
-water is a scarce resource.
-oil is an important commodity.

which best replaces the question mark?
a) region is usually peaceful.
b) climate is mostly mediterranean.
c) population is evenly distributed.
d) arabic is the most common language.

Let's name some countries in this region:
Algeria, Egypt, Saudi Arabia, Qatar, Kuwait, Tunisia, Lebanon- all of them are countries in which Arabic is the main Language!

So the correct answer is D) Arabic is the most common language. There are some exceptions, and other langauges such as Kurdish, Berber and Hebrew are also spoken there though.

Which one is the underlined word?

May consider a group  g=({0,1},+)g=({0,1},+)where  ++  will work as the xor operator like we work in boolean algebra. note here, that ‘00’ and ‘11’ are not the usual 0 and 1 that we work with everyday. the elements are  called  ‘00’ and ‘11’ and  may not mean  zero (nothing) and one (single). ‘00’ is the identity for the given binary operator +, meaning that any element operated with ‘00’ gets us that element itself.  for a set  ss  in  g′g′  having more elements than just  {0,1}{0,1}  the values for  a+b∈sa+b∈s, such that  a∈s,b∈sa∈s,b∈s, have to be first defined, only then can you determine the value of  1+11+1. the answer could possibly have been  22  if oanswer is25,000