Hello:), why does the boiling & melting point of group 7 elements increase down the group?

Which statement explains which component is likely to be more powerful in explaining a scientific phenomenon? a) component c, because a theory is often passed on possibility and not certainty b) component d, because a hypothesis is often based on possibility not certainty c) component c, because the ability to explain several occurrences in the natural world is a characteristic of a hypothesis d) component d, because the ability to explain several occurrences in the natural world is a characteristic of a theory