Final answer:
The claim that IBS symptoms typically start in late adulthood is false; IBS often begins in late adolescence or early adulthood, similar to when IBD symptoms usually first present.
Step-by-step explanation:
The statement that symptoms of IBS typically begin in late adulthood is false. IBS, or irritable bowel syndrome, can start at any age, but it most commonly begins in late adolescence or early adulthood. Regarding inflammatory bowel disease (IBD), it is important to note the differences between diseases such as Crohn's disease and ulcerative colitis, both of which are types of IBD that usually first present in the late teens or early twenties.