This is just a dictionary aside. Skip it unless you love words. I always got confused about trophic and tropic. Here's the difference.
Trophe: (from the Greek, trophikos) nourishment.
English derivatives include all the words ending in -trophy, e.g. hypertrophy, which means growth. Trophic molecules cause cells to increase their activity and their connections to neighbors. (Another example, for you doc's -- remember the "trophoblast": it feeds the embryo, right?)
Trope: (from the Greek, tropos) to turn.
English derivatives include "tropic", which comes from the Latin tropicus -- "of the solstice". The tropics are the latitudes on each side of the equator that the sun reaches maximally as the earth turns about it. And medical types will recognize "tropic", with a long O, as referring to anything that changes or turns (e.g. chemotropic, turning toward a chemical stimulus). Yes, there are tropic hormones, too -- not to be confused with our (e.g neuro-) trophic hormones!
There are some interesting English language effects. For example, consider trophy, like the one your daughter won in soccer. Although it sounds like feeding (per the above), it derives thus: from the Latin tropaeum, from the Greek tropaion, which is a form of the Greek word trope. A tropaeum or tropaion was a memorial of an ancient Roman or Greek victory, raised on the field of battle -- or in case of a naval victory, on the nearest land. The memorial commemorates the place where the battle turned. The English word comes from a French derivative, trophee. That ought to make your daughter's soccer trophy a little more interesting.
This brief tour in the dictionary suggests to me that the Greeks strongly associated feeding and nutrition (trophe) with victory in war (trope). The roots are clearly related. Interesting. Our heritage. If you actually read this far you really ought to let me know -- how many of us etymologists are there out there?
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