Hi!
You’re right that the first mitotic divisions of the zygote doesn’t make the zygote grow in size, BUT it still grows in number of cells.
I think this question was looking for a more general answer, if they had phrased it as “allows ALL organisms to grow in size” or “ALWAYS allow organisms to grow in size” you would have been correct
I also tend to think there’s always a trap somewhere in the questions!
Hope this helps!
