There is consensus among scientists that humans are causing the climate to warm. Why might this warming impact biological productivity in the deepest ocean zones? Use the figure below to aid in answering this question. A Warming may speed the formation of cold dense water in polar regions, reducing the delivery of carbon dioxide to depth, and decreasing productivity in deeper zones.

B Warming may increase the formation of cold dense water in polar regions, thereby reducing productivity in deeper zones.

C Warming may halt the formation of cold dense water in polar regions, reducing the delivery of phytoplankton to depth.

D Warming may slow the formation of cold dense water in polar regions, reducing the delivery of well oxygenated water to depth, and thereby slowing productivity in deeper zones.