| cleft lip is failure of the maxillary prominences to fuse with the medial nasal prominences |
| cleft lip is failure of the maxillary shelves to fuse with the medial nasal prominences |
| cleft lip is failure of nasal septum to fuse with the maxillary prominences |
| cleft lip occurs during the early fetal period |
| cleft lip occurs due to a single known teratogen |