Compare the leaves of a succulent plant with those of a plant that lives in the shade. Be sure to include in your answer a comparison of mesophyll, parenchyma cells, and chloroplasts. Compare and contrast spines, thorns, and prickles. Be sure to include the tissues of origin for each of these three. 2. 3. 4. Explain the pressure flow hypothesis for the transport of sugars. You may draw a diagram should you wish. Include in your explanation the cells/ tissues involved and a detailed description of the process.