Which of the following is a use of biotechnology?

Genetic engineering is a prominent use of biotechnology that involves the manipulation of an organism's genes using biotechnological techniques. This can include the addition, deletion, or alteration of DNA within an organism, allowing researchers and farmers to create genetically modified organisms (GMOs) with desirable traits, such as disease resistance or increased nutritional value.

In contrast, while animal breeding and pest control can incorporate certain biotechnological advances, they are not explicitly classified as biotechnology themselves. Animal breeding traditionally relies on selective breeding practices without necessarily involving genetic modification. Pest control may utilize genetically engineered organisms but also predominantly employs various chemical methods and practices that do not fundamentally involve biotechnological techniques. Soil analysis, on the other hand, refers to assessing soil properties and does not directly relate to the manipulation or engineering of genetic material.

Thus, genetic engineering distinctly embodies the innovative principles of biotechnology, making it the most fitting answer in this context.