Final answer:
A thyrolytic substance destroys thyroid tissue, with the term 'lytic' indicating the breakdown or destruction of cells.
Step-by-step explanation:
A thyrolytic substance refers to a compound that leads to the destruction of thyroid tissue. Given the options provided in the question, the correct answer would be B. destroys thyroid tissue. This is because 'lytic' or 'lysis' refers to the breakdown or destruction of cells. Thyrolytic substances lead to the loss of thyroid function by damaging the cells of the thyroid gland. This contrasts with substances that stimulate the thyroid gland, such as thyroid-stimulating hormone (TSH), which is released by the pituitary gland and encourages thyroid hormone production and secretion.