What toy has been used to help understand ocean circulation?

At the friction depth, water will flow in the opposite direction from the surface current?

Please explain El Nino, including the atmospheric and oceanic conditions prior to and during the event. This question is worth up to ten bonus points.

This is the submerged outer edge of a continent?

The set of conditions under which an organisms exists in nature

This is the study of classification?

The environmental factor closest to a tolerance limit for a given species, which is the most important in determining distribution at a given time.

In this form of asexual reproduction the organism develops small clones that eventually break off and become another organism?

This sort of sediment comes from land?

Which of these is a biological factor?