Questions

Calcitonin is 32-amino acid linear polypeptide hormone that is produced in humans primarily by the parafollicular cells of the thyroid, and in many other animals in the ultimopharyngeal body. It acts to reduce blood calcium, opposing the effects of parathyroid hormone.

The error lies in the first part of the sentence. After superlative adjectives, majorly two prepositions are used: of and in. We use in with a singular word referring to a place or group. Eg: I am the happiest woman in the world. We use of before plurals, before time periods such as year/month. Eg: Sunday is the best day of the week. Here, in this case, the subject is the 'school', thus, it should be 'in the school'.

Playing time of the full version of the national anthem is approximately 52 seconds. A short version consisting of first and last lines of the stanza (playing time approximately 20 seconds).