The word "and" is a connector which has the function of joining two sentences together. These sentences need a connector to combine them. From the options given the ones that have the connector are A and D. But the option D has a comma after the noun that changes the sentence. so, the most suitable answer is option A.
Hereditary is the transmission of physical and genetic qualities and attributes of parents to their offspring; the biological law by which living beings tend to repeat their characteristics in their descendants. So Susie understood very well that her height is as a result of the gene pass on to her by her parents and that good environment and eating healthy as a kid also contributes to one's physic.
