the more you go down the denser the water gets until the water is so dense that the sunlight can't reach the bottom of the ocean.
Light - even the brightest light - can only penetrate water to a certain depth, and below that depth, it is completely dark, save for some phosphorescence in certain creatures.
Its intensity decreases.
It gets darker and weakens
increase
In general, the answer is the water gets colder as you go deeper. But, there are exceptions. For example, at the Galapagos Rift there are intensely hot (hundreds of degrees) springs at depths of almost two miles.
it increases.
The pressure
No it slows down. Take for example an ocean. The deeper you go the darker it gets
light, light decreases with depth, affecting photosynthesis The deeper in the ocean you go, the less sunlight is present, and the less vigorous are algae. At some particular depth, the algae can no longer support themselves, so they cannot live at the depth (or deeper).
Because the deeper you go the more water you have on top of you, every 10 meters you go under water, you have another atmosphere on top of you, the wieg that is pressed to you is what causes the pressure
the deeper you go, the colder the ocean water gets
What do you mean increase, decrease, or stay the same? Do you mean the temperature?
the animals
lower
Temperature decreases with depth.