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.
A roundworm has no skeleton. Digestion: A roundworm has a definite digestive system that runs the length of their bodies. It has a mouth, pharynx, intestine and anus. Many are parasites and live off other animals and plants. Nervous: A roundworm has two nerve cords that transmit impulses in the roundworm. Circulation: A roundworm has no heart or formal blood vessels. Respiration: A roundworm has no formal respiratory system. Reproduction: A roundworm reproduces sexually. The female has an ovary, holds eggs in an oviduct and then passes them to the uterus, where they are fertilized. The male has sperm cells are made in the testis and stored in the vas deferens. When it is time to reproduce, the sperm cells pass through the spicule.