This is a good example of how education is failing to give us anything useful, how they are actually teaching us to focus on the wrong things.
Trying to apply a “why” to every price move is ridiculous, but something a TV commentator can do in hindsight, but not accurately. Is that what you’re training to be?
Was the price moves in Deere due to the economy firing on all cylinders or the fed pumping $80 billion per month into the system? Was it China slowing down? Was it a stock recommendation by a particular broker, or was it all hedge funds buying at the same time? Was it new buyers getting into the stock, or short sellers getting out?
There are times when the “why” is obvious, like when a new product is unveiled and people flock to buy it, or a dynamic shift in revenue. But generally, the "why" is barely discernible on the chart a few months or years later.
Tell your instructor to go back to Econ 101 for the answer: In all free markets, price is determined by supply and demand. The “why” comes later, in hindsight. By this revelation you should easily see that determining the “why” in the moment as an investment decision (or in terms of relevance to now and the future) is almost impossible. Otherwise, we would all be rich.
Trading the news is almost impossible, so why is the "why" relevant?