The term describing the manipulation of DNA in cells to produce disease-resistant crops and animals for agriculture is genetic engineering, also known as genetically modified organism (GMO) technology.

Here's why:

* Genetic Engineering: This is the broad term encompassing the direct manipulation of an organism's genes. It includes techniques like inserting new genes, deleting existing genes, or modifying existing genes to achieve desired traits.

* GMO Technology: This term specifically refers to the use of genetic engineering to create organisms with specific traits, such as disease resistance.

While other terms like biotechnology or gene editing might be used in the context of agriculture, genetic engineering and GMO technology are the most specific and accurate terms for describing the manipulation of DNA to create disease-resistant crops and animals.