I think the answer is C) Knots are related to the global coordinate system.
Natural selection. The trait that is unfavorable to the baby giraffe's survival will cause the death of giraffes with that specific gene that is responsible for a short neck vs a long neck. Natural selection causes traits that help the survival of the species will be carried throughout generations while unfavorable traits will be lost.
In some places, especially some new wells that have just been drilled,
the oil is under pressure, and it brings itself to the surface as soon as
you drill a 'pipe' for it to rise through.
In most oil wells, there's a pump bobbing up and down day and night,
pumping the oil up out of the well.
When the well is so old that even a pump isn't very effective, water is
often forced down the well under pressure, and the water forces the
oil back up through the pipe.
