I was gonna say a Scottish virgin. oh, well, you beat me to it. good job

true enough, although it is a bit simplistic to say "Plenty of pairs of species with the same number of chromosomes can't breed" Generally if they are in the same genus and often the same family and have the same number of chromosome pairs, they can have offspring. Obviously, a reptile and a mammal with the same number of chromosomes will not be able to have offspring.

as to the second part, there has been a lot of speculation on the possibility of a humanzee, human/chimp hybrid because our chromosome count differs by one, just like horses and donkeys.

The joke didn't specify how old she was, just elderly.

only if you play the Uno reverse card on them

Iron is a much more effective penetrator than lead. Also, cannon balls were often stored for long periods and transported often and needed to be sturdy enough to not deform and become useless. By the time technology had advanced enough to make a hollow iron ball and fill it with lead, they chose to fill it with gunpowder instead and add a fusing mechanism.

There is probably a subreddit for it

What it comes down to is how "clean" the genes of the original four were. The fewer genetic defects (and by defects, I mean genetic anomalies that are directly responsible for disease or disability, either dominant or recessive) that exist in the genome, the more viable the population is.