Answer:
Our solar system formed about 4.5 billion years ago from a dense cloud of interstellar gas and dust. The cloud collapsed, possibly due to the shockwave of a nearby exploding star, called a supernova. When this dust cloud collapsed, it formed a solar nebula—a spinning, swirling disk of material.
Explanation:
In this example, john's whistling is serving as a discriminative stimulus.
This procedure, studied by Ivan Pavlov, shows a stimulus ( in this case the action of John's whistling) and a response ( the cattle run to the food trough).
Pavlov studied it with dogs. He realised that when a trainer fed them, dogs salivated. So, he presented the dogs with a "stimulus" ( the sound of a metronome) and when he gave the dogs food. After a few repetitions, when the dog listened to the stimulus, it salivated.
Is she going against or for the cell phones ?
