Residential central air conditioning is rated by a Seasonal Energy Efficiency Ratio or SEER system. Since 2006, units sold in the US must have a SEER of at least 13. Air conditioning systems marked with an Energy Star meet strict US government energy-efficiency guidelines. Additional costs:
Earthworm. An earthworm is one of the animals that are classified in the Annelida phylum. Like many other animals, the earthworm has a closed circulatory system. A closed circulatory system means that the blood is confined to blood vessels and its blood recirculates so it gets maximum use. The worm uses its bodies suface area to absorb oxygen from the soil instead for using lungs or gills.
Closed circulatory systems have the blood closed at all times within vessels of different size and wall thickness. In this type of system, blood is pumped by a heart through vessels, and does not normally fill body cavities. Open circulatory system The open circulatory system is common to molluscs and arthropods.