Is it possible that all elements of an Ecosystem stay in balance with each other? If YES, what do we call such an Eco-system?

Yes,

It is considered equilibrium or homeostatis.

Explanation:

example:  plankton as a producer, minnows and young fish eat the plankton.  Larger game fish eat the littler fish.  Humans and other animals consume larger fish.  Animals die off, bacterial decay are washed into water to start it all over again.

the father in the first generation probably had the recessive colorblind trait in his x chromosome. if he and his wife both had the colorblind trait, even if she had 1 recessive and 1 dominant, then that trait would be passed on to their kids.

(since you didn't attach the family tree this is just an assumption)

what's the question?