5. It is difficult to diagnose genetic conditions because they are rarely seen and once problems start presenting themselves not only would a diagnosis need to be made. But to prove it you would have to take blood from both parents to see why they together could produce genetic conditions.
6) Down syndrome occurs when you get a smaller number of chromosomes you are supposed to inherit from each parent during conception.
7) a silent mutation is a change in DNA but does not changes the encoded and has no phenotypic effect therefore the genetic sequence is not changed
Flatworms possess excretory organs known as nephridia. Specifically as annelids, flatworms possess a variant known as metanephridia.