Im not understanding what you are trying to ask in the question.
Is there answer choices?
Is there a paragraph to go with it?
Answer:
Relative age only tells us the order in which events occurred, from the earliest to the most recent. Knowing the actual date of an event allows us to say exactly how old something is or how long ago it actually took place.
Explanation:
Answer:
b. developing a hypothesis
Answer: The length of the cell in millimetres is 0.0015.
Explanation:
Given conversion :

Thus 
Given : Length of the cell = 1.5 micrometers 
To find: Length of the cell in milllimeters (mm)
Length of the cell in milllimeters (mm) = 
The length of the cell in millimetres is 0.0015.