In the realm of quantum physics, the position uncertainty principle applies to all objects, including everyday macroscopic objects and even single-celled organisms. However, the extent to which the position uncertainty becomes noticeable or relevant depends on the mass and size of the object.
For macroscopic objects, such as a baseball or a chair, the position uncertainty is negligible and practically undetectable in everyday circumstances. The uncertainties involved in their position measurements are exceedingly tiny compared to their size and the precision of our usual measuring devices. Consequently, their behavior and motion can be well-described by classical physics.
On the other hand, for extremely small objects like individual atoms or subatomic particles, the position uncertainty becomes significant. Their quantum nature becomes apparent, and the position of such particles cannot be determined precisely. Instead, we describe their positions in terms of probability distributions. This probabilistic behavior arises due to the wave-particle duality of quantum mechanics.
As for single-celled organisms, such as bacteria or cells, they consist of a large number of atoms and molecules working together. At this scale, quantum effects tend to average out, and classical physics provides an accurate description of their behavior. The position uncertainty associated with individual atoms within these organisms does not significantly impact their overall behavior or function.
In summary, while the position uncertainty principle applies to all objects, the noticeable effects of quantum uncertainty typically become relevant at extremely small scales, such as those of atoms and subatomic particles. For everyday macroscopic objects and single-celled organisms, the position uncertainties are exceedingly small and do not noticeably affect their behavior in the classical domain.