TASK DEFINITION: In this task, you need to reverse all words of a given length in the sentence. The number of letters in a word determine its length. For example, the length of the word "apple" is 5.
PROBLEM: Sentence: 'there is a group of people standing on the beach'. Reverse all words of length '8' in the given sentence.

SOLUTION: there is a group of people gnidnats on the beach

PROBLEM: Sentence: 'the dog looks up at the cat sitting on a stone'. Reverse all words of length '1' in the given sentence.

SOLUTION: the dog looks up at the cat sitting on a stone

PROBLEM: Sentence: 'a group of zebra standing in a pen next to some rocks'. Reverse all words of length '1' in the given sentence.

SOLUTION:
a group of zebra standing in a pen next to some rocks