IPA: /ɪnˈvɪzəbli/
KK: /ɪnˈvɪzəblɪ/
In a manner that cannot be seen or noticed; not visible to the eye.
The changes in the environment can sometimes happen invisibly, without us realizing it.
Invisibly → It is formed from "in-" (meaning not) and "visibilis" (from Latin, meaning able to be seen) and the suffix "-ly" (meaning in a manner). The word "invisibly" means in a manner that cannot be seen or not able to be seen.
Think of 'not' ('in-') and 'able to be seen' ('visibilis') to remember that 'invisibly' means something that cannot be seen.