Adiffuse, nontoxic goiter is usually due to a lack of in the diet.

Answer;

Iodine

A diffuse, nontoxic goiter is usually due to a lack of Iodine in the diet.

Explanation;

-A diffuse non-toxic goiter is an enlargement of the thyroid gland without nodularity. It occurs in an endemic and sporadic distribution. It does not result from an inflammatory or neoplastic process and is not associated with abnormal thyroid function.

-Simple nontoxic goiter, which may be diffuse or nodular, is noncancerous hypertrophy of the thyroid without hyperthyroidism, hypothyroidism, or inflammation. Except in severe iodine deficiency, thyroid function is normal and patients are asymptomatic except for an obviously enlarged, non tender thyroid.

i think its b

explanation:

≅200-130 milions years ago pangea splited in 2 continents