The brain imaging technique you refer to is the MEG.
There are number of endemic species, because island isolation promotes allopatric speciation and the latter occurs when species become separated from each other to the level that prevents genetic recombination.
It could be biased or misleading.
Density = mass/volume
X = 10/50
X=.2
B.
Key word: slide
Think of sliding down a WATER slide.
