Why is this the answer?

The answer is fruit because this is a clever word puzzle that asks you to be a super-detective with letters! To solve it, you must look very closely at the words in each line and follow the rule to find the one special letter that belongs only to the first word. When you put all five of those secret letters together in the right order, they spell the final answer. Let us find the letters that spell F R U I T. First, the riddle says, "My first is in fish but no in snail." The letters F, I, S, and H are in the word "fish." The letters S, N, A, I, and L are in the word "snail." The only letter that is in "fish" but not in "snail" is the letter F. So, F is our first letter. Second, the riddle gives us "rabbit but no in tail." When we check the letters, we see that R is in "rabbit" but it is not in "tail." This is exactly the letter we need, so R is the second letter. Third, we check "up but not in down." The word "up" only has the letters U and P. The word "down" has completely different letters. This means the letter U is the special letter we are looking for in this step. Fourth, we look at "tiara but not in crown." After comparing the letters in both words, we can choose the letter I, which is in "tiara" but does not appear in "crown." This gives us the fourth letter. Finally, the last clue says, "My fifth is in tree you plainly see." Since the letter T appears in the word "tree," we know this is our final letter. When we put our five secret letters F, R, U, I, and T together, they spell the delicious and healthy word FRUIT. This makes perfect sense because the last line tells us the answer is a wonderful food for everyone to enjoy!