The tissues found within the vein if I must say are xylem and phloem. Glad I can help.
The answer is D its tightly packed cells allow for proctection against harmful substances.
Speciation is not a mechanism of microevolution.
Answer:
Cellular Respiration: a process able to extract a large amount of energy from food molecules. In eukaryotic cells oxygen is a required component. This metabolic process is the main reason that animals have elaborate gas exchange organs such as lungs, gills and other systems. The goal of these systems is, of course, to get access to oxygen and to get rid of carbon dioxide.
Explanation:
