Well, first off the spongy mesophyll does have some chloroplasts, however they are located quite far from the surface of the leaf where most of the chloroplasts are. Therefore they don't get much light and don't contribute a lot to photosynthesis in the leaf. So why should the leaf waste the energy in making chloroplasts if there is not enough light to make them all efficient enough at photosynthesis?
Explanation:
When you make the cross. You get
HH HH Hh Hh.
So the genotypic ratio - 2:2 which is also 1:1.
The phenotypic ratio - 4. Since Hh and HH are horned organisms. So they only differ in their genotypic make up.
