There are two things that cause ocean water to become denser, and those are b) the salinity of water and low temperatures.
The more salt there is, the denser the water will be - take the lake Dead Sea in Israel, Jordan, and Palestine for example.
And the lower the temperature, again, the denser the water will be - the deeper you go into an ocean, it will be more difficult to move around due to density and other things.
A not true
B not true
C could be true
D not true
DNA ligases close nicks in the phosphodiester backbone of DNA. Biologically, DNA ligases are essential for the joining of Okazaki fragments during replication, and for completing short-patch DNAsynthesis occurring in DNA repair process. There are two classes of DNA ligases.
2011 Tōhoku earthquake and tsunami<span>The 2011 earthquake off the Pacific coast of Tōhoku was a magnitude 9.0–9.1 undersea megathrust earthquake off the coast of Japan that occurred at 14:46 JST on Friday 11 March 2011, with the epicentre approximately 70 kilometres east of the Oshika Peninsula of Tōhoku and the hypocenter at an underwater depth of approximately 29 km. The earthquake is also often referred to in Japan as the Great East Japan earthquake and also known as the 2011 Tōhoku earthquake, and the 3.11 earthquake. It was the most powerful earthquake ever recorded to have hit Japan, and the fourth most powerful earthquake in the world since modern record-keeping began in 1900. The earthquake triggered powerful tsunami waves that reached heights of up to 40.5 meters. got from Wikipedia, need anything else let me know</span>