Vestigial usually refers to traits which over evolution have lost their main function and are less useful than they once were.
In number one Hunter means that he thinks the teeth were from the ancestor whale shark but are now useless or nearly useless to the current whale shark.
Speech because if the second e was not there, then the word would be spech, making the e a short vowel, and float because without the a, float would become flot, once again, making the o a short vowel.
