It may not be obvious, but the plain truth is that "tenuous" is not a synonym of "evident." "Evident" implies the presence of visible signs that lead to a conclusion, as in "He has an evident fondness for sweets." "Patent" applies to a cause, effect, or significant feature that is clear and unmistakable once attention has been directed to it, as in "There are patent defects in the building's construction." "Manifest" applies to something clearly shown or visible, as in "When they found the missing dog their relief was manifest." "Obvious" applies to something easily found or seen as in "The solution to the problem became obvious." "Plain" and "clear" are two more synonyms of "evident."