How does the brightness of a quasar compared with that of a large galaxy?

The quasar 3C 273 has an apparent magnitude of about 12.8 whereas the brightest galaxy - the Large Magellanic Cloud has an apparent magnitude of 0.9. However, in absolute magnitudes, 3C 273 has an absolute magnitude of about -26.7 very similar to our own Sun.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;