I chose sucrose, because, I think that they meant what does it lack in diet, as in it will eat what it lacks....so since it feeds on phloem tube, and the phloem translocates sucrose, thats what it must lack, as it feeds on it and needs it....
I hope im right
For the heart diagram, I chose X and Z (left atrium and rigt ventricle)
For the arrow question, I chose B (stomata)
For some unknown reason, for the chloride paper question, I chose Plant Y, upper surface (on the chart, the highest bar<<<I thought tht the one tht takes the most time to turn pink loses water rapidly, as absense of water would
not turn the chloride paper pink
Hmmmm....