ELA.6.9A Compare and contrast the stated or implied purposes (e.g., inform, influence, entertain, express) of different authors writing on the same topic. ELA.6.10A Summarize the main ideas and supporting details in text, demonstrating an understanding that a summary does not include opinions.
The shape of the breast, its size, position of nipple and their numbers are also genetically determined. Any alteration in the basic genes or the presence of a predetermined gene that governs the shape and size of the nipples can cause the nipples to be inverted.
Nipple inversion may be a developmental problem caused by tethering of the developing nipple by short ducts. The nipple will have been pulled in ever since the breast developed. New inversion occurring later in life needs to be carefully assessed to find a cause as it is sometimes due to a cancer pulling on the ducts. Inflammatory conditions like periductal mastitis and duct ectasia can also cause this problem.