When water reaches an arctic region, it sinks because it becomes
a. less dense as it gets colder and saltier.
b. more dense as it gets colder and saltier.
c. less dense as it gets colder and less salty.
d. more dense as it gets colder and less salty.

humans can cause extinction of a species through overharvesting, pollution, habitat destruction, introduction of invasive species (such as new predators and food competitors), overhunting, and other influences. explosive, unsustainable human population growth is an essential cause of the extinction crisis.

explanation:

i didn't have the answer choices , but i tried my best.