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?
I don’t know sorry but you can search on google or safari and see for icivics and it would help you
They carry oxygen to your entire body, and carry carbon dioxide away from your body to be exhaled.
Base of the substitution of the codon or frameshift mutation