6. Why do some minerals grow into large, well-defined crystals while others do not?

Mineral crystals that form when magma cools slowly are larger than crystals that form when lava cools rapidly. Minerals form when rocks are heated enough that atoms of different elements can move around and join into different molecules.

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.