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.
Answer:
The answer is D. The autonomic nervous system.
I think the correct answer from the choices listed above is option A. Sickle cell disease is caused by a change in allele. It is a disorder of the blood caused by an inherited abnormal hemoglobin. Hope this answers the question. Have a nice day.
Conservation is the protection of an organism or a group of organisms (like an endangered species or forests).
Biodiversity is the numerous amounts of species habitated in our earth. The more biodiversity, the better.
Conservation protects biodiveristy, thus, allowing more species to survive and thrive.