A single-celled organism can be classified as a prokaryote based on the absence of-

A nucleus and membrane bound organelles.

lack of nucleus.

Explanation:

A prokaryote is a simple, single-celled organism that lacks a nucleus and membrane-bound organelles.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.