Hemiptera plant. Phloem sap, which has a higher concentration of sugars and nitrogen, is under positive pressure unlike the more dilute xylem sap. Most of the Sternorrhyncha and a number of Auchenorrhynchan groups feed on phloem. Phloem feeding is common in the Fulgoromorpha, most Cicadellidae and in the Heteroptera. The Typhlocybine Cicadellids specialize in feeding on non-vascular mesophyll tissue of leaves, which is more nutritious than the leaf epidermis. Most Heteroptera also feed on mesophyll tissue where they are more likely to encounter defensive secondary plant metabolites which often leads to the evolution of host specificity. Obligate xylem feeding is a
Sugary drink tax sugary drinks that will be sold. Whether the sugary drinks tax is imposed on the seller or consumer, in both cases the tax burden is shared between both. The way that the tax burden is divided upon the consumer and seller depends on the price elasticity for sugary drinks. The tax burden will fall more on sellers when the price elasticity of demand is greater than the price elasticity of supply while on buyers when the price elasticity of supply is greater than the price elasticity of demand. The price elasticity for sugary drinks is different from country to country.