Basically its a closed loop of tubes, except for the muscular structure of the heart.
Mitochondrial DNA is circular in structure.
Prokaryotic DNA is typically circular in structure.
A plasmid is a double stranded circular DNA
Circular structure.
basin
Prokaryotes have circular DNA.
RNA is typically linear, but some RNA molecules, like viroids and circular RNAs, can be circular in structure.
Circular
The tympanic membrane.
circular
circular
A circular muscle cell is a type of muscle cell that is oriented in a circular or transverse direction around a structure. These cells are responsible for contracting and relaxing to control the size of lumens within hollow organs like the intestines or blood vessels.