Tumors of the parathyroid gland often result in secretion of excess parathyroid hormone. Considering the function of this hormone, predict the effects of such a tumor. How would the effects change if the tumor secreted calcitonin instead?

Parathyroid hormone increases the level of calcium while calcitonin hormone  decreases the level of calcium in the blood.

Explanation:

Parathyroid hormone is a type of harmone which is responsible for balancing calcium in our body. When the calcium level lowers in our body, parathyroid hormone is secreted and calcium is absorbed from the bones and fullfilled the requirement of the body. If the tumor secreted calcitonin hormone instead of parathyroid hormone, the calcium level in the blood is lowered because it acts to the opposite of parathyroid hormone.

clumped distribution, because you'de have all of the population gathered in a relatively small are.

it's the most common because it provides protection and a mate for reproduction

example: humans, seeweed, cattles, etc.