Read this paragraph from a passage.
A genetically modified organism is one whose genes have been altered. Genes from one species are inserted into a second
species. The goal of this process is to introduce a desired trait or characteristic into the second species. For example, corn is
vulnerable to certain kinds of worms that eat and destroy the corn stalks. Genes can be taken from some bacteria and inserted
into the corn. These genes from the bacteria enable the corn to produce proteins that kill the worms. This genetically modified
corn is now resistant to these pests. Other plants, such as tomatoes, have been genetically altered in a similar fashion, to remain
fresher longer.
What is the topic sentence of this paragraph?