Answer:
Explanation:
Neither do we. It's just a disconnected statement devoid of any context.
From English studies, an "an" leading the phrase means the following word starts with a vowel.
If the object is moving with varying speed, then the blank could be filled with
"unbalanced"
or
"accelerating"
If the object is dropping, then the blank could be filled with a frictional air resistance acting
"upward"
If the object is wiggling, try
"alternating"
If the object is flying, try
"aerodynamic"
I'm sure I could think of others , but it seems a waste of time guessing.
