Confusing Biology Question

Test Preparation SAT Subject Test Preparation
1

This is a question I’ve read recently and I felt quite confused
The following change is an example of which type of mutation?
Original DNA sequence: ATGGA-AGC
New DNA sequence: ATTGACAGC
I. Point mutation
II. Deletion
III. Frameshift
A. I only
B. II only
C. III only
D. I and II
E. I and III
Explanation (of the test)
A point mutation refers to a DNA mutation where a single base is changed. A frameshift mutation occurs when bases are inserted or deleted, and the entire reading frame changes. The example shows an insertion that results in a frameshift.

I don’t really understand it because there is also a point mutation. Why does the answer only have frameshift type?

2

Hey!
Well first of all this question will never EVER come on the Bio test ( 99%). DNA mutations r totally off course.
But if u still wanna know, its a frameshift mutation- Yes.
Here’s a simple rule to keep in mind: If the new sequence has changed in number of bases it is frameshift. Now count the bases in Sq1- 8
New Sq- 9
Additionally its an insertion frameshift mutation and not a deletion, so eliminate options B D nd E.
As the number of bases changes pick C :)>-