You are a forensic biologist and have been asked to review the files of an old, unsolved murder case. The autopsy report is missing a lot of important information, but you read that the victim had a thymus gland that was just starting to shrink. Based on this information alone, what can you conclude about the victim?

That the victim had just reached puberty.

Explanation:

Unlike most organs that grow until the age of maturity, the thymus enlarges throughout childhood but slowly shrinks from the onset of puberty and throughout adulthood. As the thymus shrinks, its tissues are replaced by adipose tissue. The shrinking is due to the reduced role of the thymus in adulthood — the immune system produces most of its T cells during childhood and requires very few new T cells after puberty.