When committing the fallacy of false cause, a speaker assumes?

The answer to this question is that when one thing follows another, the first is the cause of the second.
Examples of fallacy of false cause:
- After my mother eat the tomatoes, she developed dementia. Therefore, tomatoes cause dementia.
- After taking vaccines, my Daughter developed autism. Therefore, vaccines cause autism

This one hard but um i have no idea i’m sorry