Final answer:
Plants usually produce fruits after fertilization occurs, with the ovary of the flower developing into a fruit. However, fruit can also be produced without fertilization through parthenocarpy or apomixis.
Step-by-step explanation:
The statement that plants that have been fertilized can produce fruits is generally true. In most cases, after plants are fertilized, the ovary of the flower develops into a fruit. This fruit formation process helps in protecting the seeds and supports their dispersal. However, there are exceptions to the rule in the form of parthenocarpy, an occurrence where fruits are produced without fertilization leading to no seed development or the abortion of initiated seeds. Moreover, some plants can reproduce through apomixis, a process where seeds are produced without fertilization.