Where, if at all, should a comma be added in the following sentence?

many people believe that global warming is real but they are not sure what can be done about it.

after the word but
after the word real
no comma should be added.
after the word believe

2. where, if at all, should a comma be added in the following sentence?

maya is determined to go to medical school or join the peace corps after college.

after the word or
no comma should be added.
after the word corps
after the word school

3. where, if at all, should a comma be added in the following sentence?

when novelists set out to write a work of historical fiction they craft a story that takes place during a particular era in the past.

after fiction
after era
no comma should be added.
after story

4. where, if at all, should one or more commas be added in the following sentence?

many wealthy businesspeople for example may have no time to enjoy their money.

after example
after businesspeople and after example
no comma should be added.
after businesspeople

5. where, if at all, should a comma be added in the following sentence?

dogs that do not shed are often called hypoallergenic.

no comma should be added.
after dogs
after dogs and after shed
after shed

6. where, if at all, should one or more commas be added in the following sentence?

the country of haiti which gained its independence from france in the early 1800s has seen much political and economic hardship.

after haiti and after 1800s
no comma should be added.
after 1800s
after haiti

7. which change corrects the following sentence?

rachel claims to be a vegetarian, however, she eats seafood.

replace the comma after however with a semicolon.
delete the comma after however.
replace the comma after vegetarian with a semicolon.
delete the comma after vegetarian.

8. which change, if any, corrects the following sentence?

when the ball drops at midnight in new york city's times square, millions of americans on the east coast will celebrate the new year.

add a comma after coast.
delete the comma after times square.
change the comma after times square to a semicolon.
no change is necessary.

9. which change, if any, corrects the following sentence?

i made an appointment with an optometrist because, i need a stronger prescription for my glasses.

add a comma after optometrist.
no change is necessary.
delete the comma after because.
add a comma after optometrist and delete the comma after because.

10. which change, if any, corrects the following sentence?

psy, a korean entertainer had a worldwide hit in 2012 with the song gangnam style.

delete the comma after psy and add a comma after entertainer.
no change is necessary.
delete the comma after psy.
add a comma after entertainer.

:1- A comma should be added in the following sentence after the word real because a comma is used between two Independent clauses separated by for, and, nor, but, or, yet, so

Many people believe that global warming is real, but they are not sure what can be done about it.

2. No comma should be added in the following sentence because there is not a new subject after the word OR

Maya is determined to go to medical school or join the Peace Corps after college.

3. A comma should be added in the following sentence after fiction because commas are used to  separate Independent Clauses from Dependent Clauses.

When novelists set out to write a work of historical fiction, they craft a story that takes place during a particular era in the past.

4. Two commas should be added in the following sentence: after businesspeople and after example.

This is because commas are used to offset transitional expressions such as for example

Many wealthy businesspeople, for example, may have no time to enjoy their money.

5. No comma should be added because “that do not shed “ is a restrictive relative clause.

Dogs that do not shed are often called hypoallergenic.

6. Commas should be added after Haiti and after 1800s because “which gained its independence from France in the early 1800s” is a non-restrictive relative clause. This type of relative cause just gives additional information so is set off between commas.

The country of Haiti, which gained its independence from France in the early 1800s, has seen much political and economic hardship.

7. The  change that corrects the following sentence is :Replace the comma after vegetarian with a semicolon. However is a conjunt. Conjuncts are always set off between a period or semicolon and a comma.

Rachel claims to be a vegetarian; however, she eats seafood.

8. No change is necessary in the following sentence.The dependant clause is at the beginning of the sentence so the comma is neccesary.  

When the ball drops at midnight in New York City's Times Square, millions of Americans on the East Coast will celebrate the New Year.

9. Deleting the comma after because corrects the following sentence. It is not neccesary to put a comma when the dependant clause comes after the main clause.

I made an appointment with an optometrist because I need a stronger prescription for my glasses.

10.It is necessary to add a comma after entertainer because “a Korean entertainer” is  parenthetical information.

PSY, a Korean entertainer, had a worldwide hit in 2012 with the song Gangnam Style.

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answer; (d) i believe the best answer is ; ///people said that man could not fly, but in 1903, orville and wilbur wright made the first sustained powered flight in a heavier- than-air machine;