Hiv frequently mutates and changes its surface antigens, making the development of a vaccine difficult. true false

Match the following. match the items in the left column to the items in the right column. 1. foreshocks process used to locate the epicenter of an earthquake 2. magnitude newer magnitude scale that measures the amount of moved (displaced) rock along a fault to determine the strength of an earthquake 3. mercalli intensity scale measure of the total amount of energy released during an earthquake 4. moment magnitude scale areas on active faults where a major earthquake hasn't occurred in a long time 5. richter scale mini-quakes that usually occur before a major earthquake 6. seismic gaps scale that measures the effects or severity of an earthquake 7. triangulation scale of magnitude based on the size of seismic waves produced by an earthquake

What's wrong with this ecological pyramid? (multiple choice)1. secondary consumers should be at the bottom of the pyramid2. the sun has an arrow leading to decomposers 3. primary consumers should come after the sun4. energy retained should increase from the bottom to the top5. the sun should be at the bottom of the pyramid

During convection, less dense fluid rises and denser fluid sinks.