Final answer:
A weak relationship is when two variables are connected but one does not strongly imply the existence of the other. The false cause fallacy is an example where correlation is mistaken for causation. For instance, substance A's non-thermal effect on B and B's on C doesn't guarantee A's effect on C.
Step-by-step explanation:
A weak relationship refers to a connection between two variables where the presence of one does not necessarily imply the presence of the other, or the relationship is not strong enough to draw a firm conclusion. An example of a false cause fallacy, which is a type of weak relationship, would be assuming that an increase in ice cream sales causes an increase in shark attacks because both happen in the summer. This is a fallacy because it confuses correlation with causation; the two events are not causally connected and the underlying factor of warmer weather is independently affecting both.
In another instance, consider a situation where substance A alters the state of substance B without using heat (non-thermal). If substance B alters substance C in the same non-thermal manner, it does not imply that substance A will alter substance C non-thermally as well. This illustrates a scenario where weak inductive reasoning can lead to incorrect conclusions if one assumes a direct relationship where there is none.