Sentence Correction

I am struggling with these two SC questions and I need some explanations for their answers please:

Question 1:

47. According to scientists at the University of California, the pattern of changes that have occurred in human DNA over the millennia indicate the possibility that everyone alive today might be descended from a single female ancestor who lived in Africa sometime between 140,000 and 280,000 years ago.

(A) indicate the possibility that everyone alive today might be descended from a single female ancestor who
(B) indicate that everyone alive today might possibly be a descendant of a single female ancestor who had
(C) may indicate that everyone alive today has descended from a single female ancestor who had
(D) indicates that everyone alive today may be a descendant of a single female ancestor who
(E) indicates that everyone alive today might be a descendant from a single female ancestor who

The answer is D. But, shouldn't the verb be in the plural ''indicates'' since its subject "pattern of changes" has a plural verb right after it "that have occurred"?

Question 2:

56. Acid rain and snow result from the chemical reactions between industrial emissions of sulfur dioxide and nitrogen oxides with atmospheric water vapor to produce highly corrosive sulfuric and nitric acids.
(A) with atmospheric water vapor to produce highly corrosive sulfuric and nitric acids
(B) with atmospheric water vapor producing highly corrosive sulfuric and nitric acids
(C) and atmospheric water vapor which has produced highly corrosive sulfuric and nitric acids
(D) and atmospheric water vapor which have produced sulfuric and nitric acids which are highly corrosive
(E) and atmospheric water vapor to produce highly corrosive sulfuric and nitric acids

The answer is E. I thought the word "between" is used to refer to relationships involving only two objects so how come we are including "atmospheric water" too? Shouldn't the answer be A instead?

Thanking you in advance.

Sak32 wrote:I am struggling with these two SC questions and I need some explanations for their answers please:

Question 1:

47. According to scientists at the University of California, the pattern of changes that have occurred in human DNA over the millennia indicate the possibility that everyone alive today might be descended from a single female ancestor who lived in Africa sometime between 140,000 and 280,000 years ago.

(A) indicate the possibility that everyone alive today might be descended from a single female ancestor who
(B) indicate that everyone alive today might possibly be a descendant of a single female ancestor who had
(C) may indicate that everyone alive today has descended from a single female ancestor who had
(D) indicates that everyone alive today may be a descendant of a single female ancestor who
(E) indicates that everyone alive today might be a descendant from a single female ancestor who

The answer is D. But, shouldn't the verb be in the plural ''indicates'' since its subject "pattern of changes" has a plural verb right after it "that have occurred"?

Question 2:

56. Acid rain and snow result from the chemical reactions between industrial emissions of sulfur dioxide and nitrogen oxides with atmospheric water vapor to produce highly corrosive sulfuric and nitric acids.
(A) with atmospheric water vapor to produce highly corrosive sulfuric and nitric acids
(B) with atmospheric water vapor producing highly corrosive sulfuric and nitric acids
(C) and atmospheric water vapor which has produced highly corrosive sulfuric and nitric acids
(D) and atmospheric water vapor which have produced sulfuric and nitric acids which are highly corrosive
(E) and atmospheric water vapor to produce highly corrosive sulfuric and nitric acids

The answer is E. I thought the word "between" is used to refer to relationships involving only two objects so how come we are including "atmospheric water" too? Shouldn't the answer be A instead?

Thanking you in advance.

In Question 1:
You can rule out A and B because we need singular verb because the subject is singular "the pattern"...whenever you see the subject with prepositional phrase such as....x of something....y of something....then the subject will be x and y. You can basically ignore the part "of something"
C is out because the usage of "had" is not appropriate.
Between D and E. E uses wrong idiom...descended from is correct idiom but not descendant from...it should be descendent of so D is the correct answer.
Regarding your query for SV agreement to clarify further....the pattern of changes...here the pattern is the subject not the changes....you can ignore the changes.....

Question 2:

The sentence structure is

"...between industrial emissions of sulfur dioxide and nitrogen oxides and atmospheric water vapor to produce highly corrosive sulfuric and nitric acids.."

The correct idiom is between X and Y

X = industrial emissions of sulfur dioxide and nitrogen oxides
Y = atmospheric water vapor to produce highly corrosive sulfuric and nitric acids

rakeshd347 wrote:

Sak32 wrote:I am struggling with these two SC questions and I need some explanations for their answers please:

Question 1:

47. According to scientists at the University of California, the pattern of changes that have occurred in human DNA over the millennia indicate the possibility that everyone alive today might be descended from a single female ancestor who lived in Africa sometime between 140,000 and 280,000 years ago.

(A) indicate the possibility that everyone alive today might be descended from a single female ancestor who
(B) indicate that everyone alive today might possibly be a descendant of a single female ancestor who had
(C) may indicate that everyone alive today has descended from a single female ancestor who had
(D) indicates that everyone alive today may be a descendant of a single female ancestor who
(E) indicates that everyone alive today might be a descendant from a single female ancestor who

The answer is D. But, shouldn't the verb be in the plural ''indicates'' since its subject "pattern of changes" has a plural verb right after it "that have occurred"?

Question 2:

56. Acid rain and snow result from the chemical reactions between industrial emissions of sulfur dioxide and nitrogen oxides with atmospheric water vapor to produce highly corrosive sulfuric and nitric acids.
(A) with atmospheric water vapor to produce highly corrosive sulfuric and nitric acids
(B) with atmospheric water vapor producing highly corrosive sulfuric and nitric acids
(C) and atmospheric water vapor which has produced highly corrosive sulfuric and nitric acids
(D) and atmospheric water vapor which have produced sulfuric and nitric acids which are highly corrosive
(E) and atmospheric water vapor to produce highly corrosive sulfuric and nitric acids

The answer is E. I thought the word "between" is used to refer to relationships involving only two objects so how come we are including "atmospheric water" too? Shouldn't the answer be A instead?

Thanking you in advance.

In Question 1:
You can rule out A and B because we need singular verb because the subject is singular "the pattern"...whenever you see the subject with prepositional phrase such as....x of something....y of something....then the subject will be x and y. You can basically ignore the part "of something"
C is out because the usage of "had" is not appropriate.
Between D and E. E uses wrong idiom...descended from is correct idiom but not descendant from...it should be descendent of so D is the correct answer.
Regarding your query for SV agreement to clarify further....the pattern of changes...here the pattern is the subject not the changes....you can ignore the changes.....

Thank you for your answer but I still have one more issue. If like you said "pattern of changes" is indeed singular than why does the verb that comes right after it in the plural form "have occurred"? Shouldn't it be "has occurred"?