The Answer To This Question Is: <u>D) the particles in the substance connect more strongly to one another.</u>
The reason for this answer is because:
It cant be the first answer because a particle cannot change in mass. That would be impossible (search it, if you want to make sure).
It cant be the second one either because particles cannot change shape due to them being circles.
It cant be the third one too because a single particle again, cannot change shape, mass, or softness.
However, particles <em>can</em> be close and tight together (making it a solid), loose and free (making it a liquid), or far apart (making it a gas).
This makes the last option a reasonable option.
<em><u>Thank you for your time, and have a nice day ahead m8! </u></em>