Could two parents with cleft-chin have a child without cleft-chin?

Cleft chins were believed to be a dominant trait: if two parents had cleft chins, their kids could have a cleft or might not  But it turns out a cleft chin is too complicated to be simply dominant. Two parents without a cleft have kids with cleft chins way more often than predicted with this simple model.

Explanation:

the contamination

we are putting to many trash.

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.