The question asks about hormonal deficiencies causing three conditions. (a) Diabetes mellitus is caused by deficiency of insulin, which is a hypoglycemic hormone mentioned in the context under functions of hormones. (b) Goitre refers to enlargement of the thyroid gland, which occurs due to deficiency of thyroid hormones, often caused by iodine deficiency in diet. The context mentions Exopthalmic goitre as a form of hyperthyroidism, but simple goitre results from thyroid hormone deficiency. (c) Cretinism is caused by thyroid hormone deficiency during development, as indicated in the context which describes hypothyroidism effects including 'retardation, low intelligence quotient, abnormal skin' - characteristic features of cretinism.