Agraph used to study the stars is a distance-time graph a velocity-time graph a wind velocity diagram an hr diagram

A distance-time graph is graph that represents the speed of an object and the velocity of an object is its speed in a particular direction.
A velocity-time graph is a graph that represents the acceleration or velocity of an object.
A wind-velocity diagram is a diagram that measures wind speed, or wind flow velocity.
A HR Diagram (Hertzsprung-Russell Diagram) is a scatter graph of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their spectral classifications or effective temperatures.
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Bacteria have complex internal structures.