Answer:
False, but be sure you read what follows.
Explanation:
False: Heart disease and Most Cancers are not viruses. Or at least as far as I know. However complicating the issue is the fact that after a viral infection, heart disease can develop.
Cancer is another example, and the answer again is not black and white. 16% of all cancers can trace their beginnings to a bacteria or virus. That leaves 84% whose beginnings are not that clear.
The question is not black and white. I'd be careful how you think of it. If something is a complication, is that a direct cause? I still think the answer is false, but don't be surprised if your instructor disagrees. Move on to something a little less black and white.