We don't use a "two kingdom biology" today, though. There may be as many as six kingdoms, if we follow T. Cavalier-Smith's argument (A revised six-kingdom system of life, 1997), and anyway modern biology uses the three-domain system as the broadest taxonomic division.
As you ought know, none of the six systems of taxonomy is really satisfactory enough to insist that one or the other must be used because it is perfect.
But all of them are arbitrary and can be useful when the circumstances avail themselves.
But my reasoning is that since Genesis speaks only of Plants and Animals, a modern reader should comprehend what the writers were saying, and they should utilize the Two Kingdom System sincethe imlication is that all life forms were created during the six eras of geological time.
(Which side are you on?
Are you a scientist taking the opposition to my theistic evolution or a programmed loyal denominational church person maintaining that Genesis contradicts science???)