What property of GFP makes it useful in visualization techniques?

The intrinsic fluorescence properties of GFP (Green Fluorescent Protein) are what make it particularly useful in visualization techniques. GFP emits green light when exposed to ultraviolet or blue light due to its unique molecular structure, which allows it to fluoresce without needing any additional dyes or complex reagents. This intrinsic fluorescence allows researchers to track and visualize proteins within living cells and organisms in real time, providing valuable insights into cellular processes and dynamics.

In contrast, other options do not provide the same level of utility for visualization. For example, while some proteins can change color upon activation, this property is not a characteristic of GFP and may not always lend itself to the same clarity in visualization. Additionally, although affinity for binding to other molecules and the ability to aggregate in cells can be important properties in different contexts, they do not contribute to the intrinsic ability of GFP to function as a fluorescent marker. It is the inherent fluorescence, which is stable and allows for straightforward imaging, that underpins its applications in molecular biology and biotechnology.