To help explain these uncertainties, four hypotheses have been put forth: The " de novo/maternal-precursor hypothesis" attempts to explain the observation that, due to a dramatic centrosome reduction, rodent sperm lack a recognizable centriole, yet centrioles are observed when the embryo reaches the 64-cell stage (Schatten et al. 1986; Gueth-Hallonet et al. 1993).
Finally, the crystal structure of Lin28 in complex with three different let-7 precursors has provided a model to explain how the two RNA-binding domains of Lin28 together may accommodate different RNA secondary structures [ 26].
However, the computing of efficiencies is prone to difficulties and errors, since it requires computing the quantities precursors sets which are required to explain the measured composition of outputs, although some of the internal products may be recycled within cycles [ 16].
NAD+ is a bit complicated to explain, but it's believed to be a precursor to anti-aging in cells and Elysium says its ingredients increase these levels.
Photothermal and/or photochemical mechanisms may be invoked to explain the nanoparticle growth, depending on the laser, precursor, and matrix.
The author goes on to explain how individuals were attracted to Dianetics, the precursor to Scientology.
In an eerie precursor of today's concerns about American subprime mortgages, he is asked to explain, too, what he means by "loans secured by real-estate mortgages".
Life-forms appeared with no obvious precursors, it says, too quickly for a random process of mutation and survival of the fittest to explain it.
Quayle goes on to explain that his son's connection to the "Dirty" chain of websites was limited to a few introductory remarks made on "Dirty Scottsdale," a precursor to TheDirty.com that has since been retired.
