What must happen to tracheids and vessel elements before they can functions in xylem?

What did Gregor Mandel discover about recessive traits? How much gas does a 767 burn? Is liking spicy food genetic or environmental If is genetic is it passed down from generations? What is the fracters of 100? How many calories does barium liquid have? Do solids take up space? If it is 0800am PDT what time is EST? Neutrons are found in all atoms except for most atoms of nitrogen.? What was the biggest snow storm in Transylvainia? What are the average high weather for Hawaii in the summer? Which of these processes brings in large macromolecules and particles by the formation of a vesicle in the outer membrane? How many thousand pounds in a Trillion pounds? Does it snow in London by feb? Count plant carpels? Which is not a type of leukocyte erythocyte monocyte or basophil? How many atoms is in a iron bar? What production is linked to an increase in the occurrences of skin cancers caused by the holes in the ozone layer? Is alpha methyl-d- glucoside a reducing sugar? What is found on the surface area where contour lines are shown on top of each other? When you eat food your body gets the chemical energy stored in it in turn your muscles store this chemical energy . when does this chemical energy become useful to you?