PLEASE HELP IM TIMED WILL MARK BRAINLIEST 13 POINTS Which statement best explains how galaxies are held together?

A. Thermal energy generated by stars holds galaxies together
B. Magnetic forces among the components of galaxies holds galaxies together
C. Electrical energy generated by planets holds galaxies together
D. Gravitational forces among stars and other components of galaxies holds galaxies together

What produces light and all other electromagnetic waves? a) the photoelectric phenomena b) heated metals c) charged particles d) radioactive samples (pls explain if you can : )

Utah's great salt lake has an average salinity seven times higher than that of the oceans. very few multicellular organisms live in this harsh environment. an example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. these brine shrimp must available hint(s)utah's great salt lake has an average salinity seven times higher than that of the oceans. very few multicellular organisms live in this harsh environment. an example is the brine shrimp, which must devote a large portion of its metabolic energy to osmoregulation. these brine shrimp must pump water back into their cells to counter its loss due to osmosisactively pump water back out of their cells to counter its inflow due to osmosissynthesize membranes that are impermeable to substances that upset osmotic balanceactively pump salt back out of their cells to counter its inflow due to osmosis

If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?