Most careful American writers would place a comma before "as", because what follows "as" is a dependent clause. However, there is an exception for short clauses, and some would consider this clause short enough not to need a comma.
When did treaties become necessary?
when did it become an English colony
While education and teacher certification is essential, it is not necessary. There are many colleges that can help get a certification for ESL, but again not necessary. You can teach online or tutor from home or at a school to children and adults who do not know english, but you must be fluent in english yourself.
there is about 11 years of school that is necessary.
It has become necessary to write this because of the question posed.
St George's Day is not particularly significant in England - although St George is the Patron Saint of England. Most English people do not know when St George's Day is. It is not a public holiday. Christmas, Easter and English Bank Holidays are much more significant.
math Mathematics shall be necessary, houwever you may need an English option for Reading and Spelling purposes.
Hematology
no, it is not necessary
No, there are lots of Russians that have become astronauts.
English became a national language through a combination of historical events, including the Norman Conquest in 1066 and the subsequent development of English as the language of the ruling class. The spread of the British Empire also played a significant role in the global adoption of English as a national and international language.
Any resource necessary to the survival of populations in an ecosystem may or will become an abiotic factor.