They are circumferences
The circles could be in 2 planes that are parallel to each other. Lines and planes can be parallel. Lines of latitude are examples of circles that are in parallel planes.
No. A circle has no straight lines. You can approximate circles with very small straight lines (that's how a computer draws circles) but mathematically, no.
lines of latitude are horizontal lines that form circles and that run in the same direction as the equator
If two circles are drawn using the same centre, the two lines of the circles are parallel as they don't meet each other.Two straight lines (think of railway tracks) are drawn next to each other, but never meet, they are parallel lines.
Circles and curved lines.
Because they make big circles around the Earth.
The tracheal rings of the fetal pig are complete, not incomplete circles. The tracheal rings help to keep the airways open.
draw lines and connect them
Great circles.
great circles
yes
great circles