What causes water to become denser when it is carried to the poles by surface currents?

Look at the picture below . what does this picture represent ?

Ascientist separates a population of mice into two groups. what would most likely increase the rate of speciation in this population. a. teach the two groups different tricks b. allow the two groups to breed with each other c. put the two groups in different environment d. have the two groups live in identical ecosystems

Which best describes carbon dioxide’s path out of the body