The answer is C), playing a simple scale.
The sentence should be this: She demonstrates how to tune her instrument and she also played the simple scale.
Answer: Krill
A primary consumer is an herbivore
I think you would omit the comma because the pause there sounds a little awkward to me. But not sure, it could also be the leave it as it is.
Answer:
D. Roger Federer has won at least five U.S. Open tennis tournaments.
Explanation:
If roger won five he won five, its a fact