First of all, you might want to spell DEFENSE correctly.
no because it is in the body
External defenses - Includes skin and mucous membranes. Internal defenses - Includes phagocytic cells, inflammatory responses, and antimicrobial proteins.
These lines are perpendicular: _|
Earl's-defense is a system of fortifications for protection.
4
The gastroderm is the inner layer of cells that lines the gut or digestive cavity of cnidarians such as jellyfish and corals. It is involved in digestion, absorption of nutrients, and in some cases, defense mechanisms.
when the first and the second lines of defense have already been overcome.
Railway tracks electrical lines
Did you mean "real world examples of parallel lines"? If so, railroad tracks are a perfect example.
Yes it is a good line of defense.
the lines of the brooklin bridge
Communication channels.