When dna was discovered, they saw that the strands of the double helix are lined up in the opposite direction of each other. what kind of orientation is this?

When DNA was discovered, Watson and Crick saw that the strands of the double helix are lined up in the opposite direction of each other. This type of orientation is called the antiparallel orientation.

The antiparallel orientation is a type of orientation showing two polymers present side by side but running in the opposite direction. The best example of this is the deoxyribo nucleic acid (DNA). DNA molecule is made up of a pair of polynucleotide strands which are antiparallel. The antiparallel orientation of the DNA facilitates the hydrogen bonding between the two complimentary strands. This is also important for the processes of DNA replication and transcription.

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.