Which of the following is an example of modern biotechnology?

Gene splicing is a clear example of modern biotechnology because it involves manipulating an organism's genetic material directly, allowing for precise alterations to DNA. This technique enables scientists to identify specific genes responsible for desired traits and either insert, delete, or modify these genes within an organism's genome. This process can lead to the development of genetically modified organisms (GMOs) that exhibit improved characteristics, such as increased resistance to pests or enhanced nutritional content.

In contrast, cross-pollination and crop rotation are traditional agricultural practices that have been used for centuries to improve plant varieties and soil health, without the genetic manipulation that characterizes modern biotechnology. Seed treatment, while it may involve chemical processes or fungicides to enhance seed performance, does not involve any alteration of the plant's genetic makeup and thus does not fit the definition of modern biotechnology.