Final answer:
Hair loss or changes in hair growth can be caused by radiation therapy, diabetes, and infections, but the ageing process is the least suggestive of hair changes.
Step-by-step explanation:
Hair loss is a side effect of radiation therapy, but it only occurs locally in the area being treated. For example, if radiation therapy is done on the head, hair loss may occur on the head, including eyebrows and lashes. However, if radiation therapy is done on the hip, hair on the head will not be affected.
Hair loss can also be caused by various factors related to diabetes such as hormonal imbalances, nutritional deficiencies, and autoimmune issues.
An infection can also lead to changes in hair growth or hair loss. Scalp infections like fungal infections or conditions like alopecia areata can cause hair loss.
The ageing process is the LEAST suggestive of changes in hair growth or loss of hair. Hair thinning and loss are natural processes that occur with age, but they are not exclusive to ageing and can be influenced by various factors.