Answer:
A millimeter is [tex]\frac{1}{1000}\text{th}[/tex] meter.
Step-by-step explanation:
We have been given an incomplete sentence. We are asked to fill in the blank for given statement.
A millimeter is ______ meter(s).
We know that 1 meter equals 1000 millimeter.
This means that 1 millimeter is [tex]\frac{1}{1000}\text{th}[/tex] part of a meter, therefore, option D is the correct choice.