<span>If the density of ice were greater than water, ice would sink to the bottom of oceans/seas/lakes etc. This ice would cool the water so much that more water would freeze, and the entire body of water would soon be a giant block of ice! You can imagine how this would affect aquatic life</span>
Hippocampus. This is a type of amnesia called anterograde amnesia which manifest as inability to form new memories after the brain was damage. This can also lead to impairment of remembering new facts and events. The area in the brain that is associated learning and memory is the hippocampus. Any damage in this area whether due to hypoxia, stroke, or any form of pathology can cause anterograde amnesia. This is a part of the limbic system that plays a role in consolidation of short term to long term memory and spatial memory that allows us to navigate. This area is located under the cerebral cortex.
Naturally occurring means that they are formed by a natural process. Identify the two most abundant elements in Earth's crust.