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.
The desert and tundra are alike because they both have limited available water.
alpha cells are glucagon and beta cells are insulin
Answer:
The bottleneck effect, also known as a population bottleneck, is when a species goes through a "bottleneck" event that suddenly significantly reduces its population. ... The bottleneck effect is a type of genetic drift, which is defined as a random change in allele frequencies.
