Answer:
The answer is: Growth hormone (GH)
Here's why:
* **Growth hormone (GH)**: This hormone is produced by the pituitary gland and is essential for stimulating cell division and growth throughout the body. It directly affects tissues like bone, muscle, and cartilage.
* **Thyroid releasing hormone (TRH):** This hormone stimulates the production of thyroid stimulating hormone (TSH), not directly involved in mitosis or differentiation.
* **Thyroid stimulating hormone (TSH):** This hormone regulates thyroid function, not directly involved in mitosis or differentiation.
* **Adrenocorticotropic hormone (ACTH):** This hormone stimulates the adrenal cortex to release cortisol, which is involved in stress response and metabolism, not directly involved in mitosis or differentiation.