The correct answer is "they originate as pockets, rather than forming continuous tubes".
Lymphatic capillaries are very small vessels located between cells. Their function is to absorb and process extracellular fluid. They have very thin walls and larger diameter than blood capillaries. Another important characteristic is that they have closed ends, permitting the extracellular fluid to flow in but not out.
Air pollution. Cleaner burning than other fossil fuels, the combustion of natural gas<span> produces negligible amounts of sulfur, mercury, and particulates. Burning</span>natural gas does<span> produce nitrogen oxides (NOx), which are precursors to smog, but at lower levels than gasoline and diesel used for motor vehicles.</span>
