Ardor is a fiery synonym for passion; it means “great warmth of feeling” or “zeal.” Ardor comes from the Latin verb ārdēre “to burn.” Like fire, which burns bright until extinguished, the word ardor has a temporariness to it, often implying intense but short-lived bursts of feeling, as in youthful ardor, or revolutionary ardor. When the fire of enthusiasm wanes, ardor may be said to have cooled or dampened.
To call something minuscule is to emphasize how tiny or unimportant that thing is. While small effectively lets a reader know that an item is of limited size, minuscule adds greater specificity. Now about the spelling: it would be perfectly logical to presume that the u in minuscule is an interloper, and that the term should be spelled miniscule from mini- “of a small size.” The fact is, minuscule comes from the Latin word minus meaning “less,” so minuscule is the standard spelling. Even so, miniscule occurs with such frequency that some consider it a variant spelling.
To cause something is to bring it about. To precipitate something is to accelerate its occurrence, or to bring it about prematurely, hastily, or suddenly. As you might expect, this verb is usually used to talk about undesirable or even perilous outcomes: crises, collapses, disasters, and downfalls are all things that are precipitated. On occasion, you’ll hear it used to discuss swift change that is favorable, but more often than not precipitate connotes a steep downward trajectory.