A man with opalescent dentine marries a woman with normal teeth. One of the man's parents has opalescent dentine; the other parent of the man was normal. Neither parent of the woman had opalescent dentine. What ratio of affected (those with opalescent dentine) to unaffected (normal) would be found in the children produced through the marriage of the man and woman in the first sentence of this problem? What genotypes are associated with the ratios?

a. 3DD;1Dd
b. 1Dd:1dd
c. 3dd:2Dd
d. 3dd:4DD
e. none of these

answer; /// the correct )

well the answer is 2!

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.