Explanation

The paragraph consist of three parts ,which are:

Topic of sentence 

Supporting detail 

Concluding Sentence

Explanation

metropolitan میٹروپولیٹن

of or relating to a large city, its surrounding suburbs, and other neighboring communities: 

Explanation

• Doctor: Nurse:: leader: Follower
• ***
• Just as a nurse follows the doctor's instructions, so also a follower works as directed by the leader
  

Explanation

• hydrogen gas can not use as fuel
• ***
• "AS " is best to keep the meaning of the original sentence
• ****
• TWO REASONS WHY WE USE THE "AS" PREPOSITION IN THE ABOVE SENTENCE

• 1: We use as with a noun to refer to the role or purpose of a person or thing:
• Fuel is a noun 
• ****
• 2: "AS" preposition is used in those sentences in which two things indicate the same meaning or use the same purpose
• For example 
• Hydrogen can also serve as fuel. 
• 
  

Explanation

Sa'd was born in Medina 590 CE

Explanation

On December 20, 1777, the Kingdom of Morocco became the first country in the world to recognize United States independence.

only a year and a half after the U.S. Declaration of Independence was issued.