ᴛʜᴇ ᴘᴀʀᴛɪᴄʟᴇs ᴏғ ᴍᴀᴛᴛᴇʀ ᴀᴛᴛʀᴀᴄᴛ ᴇᴀᴄʜ ᴏᴛʜᴇʀ.
Answer:
the particles of matter attract each other
hope it helps