The medical term meaning lack of formation or development is: A) ectogenesis. B) antiplasty. C) aplasia. D) hyperalgia.

## Step 1<br />The problem is asking for the medical term that means "lack of formation or development". We need to understand the meaning of each option to find the correct answer.<br /><br />## Step 2<br />Let's analyze each option:<br />- Ectogenesis refers to the development of an organism outside the body of the parent.<br />- Antiplasty is a term used to describe a surgical procedure that involves the removal of tissue.<br />- Aplasia is a term used to describe the absence of organ or tissue development.<br />- Hyperalgia is a term used to describe an increased or excessive sensation of pain.<br /><br />## Step 3<br />From the above analysis, it is clear that the term that means "lack of formation or development" is aplasia.