Because it happens at the level of individual particles, you need quantum physics to get precise.

To analyze the universe on the level of individual particles, quantum mechanics is required.

When you get down to the level of individual particles, probability behaves quite differently.

At the level of individual particles, the fields are always oscillating.

OK, some uncertainty principle might be at work on the level of elementary particles, but not of whole bodies!

At the level of single particles, Newton's Laws fall apart.

When you get to the level of single particles, such as electrons and photons, quantum physics takes over.

Intervention households were also found to have lower levels of small particles and carbon monoxide.

Simpler systems could work on large scales but would fall apart at the level of individual particles.

And at the level of nuclear particles, quantum mechanics turned nature into a game of probability.