1. Exoskeleton-<span>Arthropods are invertebrates, which means their bodies do not have internal bones for support. To compensate for this, they produce a hard exoskeleton made of chitin, a mixture of lipids, carbohydrates and protein, which covers and protects their bodies like a suit of armor. As arthropods grow, they must shed or molt their exoskeletons. They first produce new, softer exoskeletons underneath the old ones. Once their hardened, old coverings crack and shed, they sport roomier, albeit soft, exoskeletons. Arthropods are incredibly vulnerable during the molting process, and will often hide until their new exoskeletons harden.</span> 2. Segmented bodies-Arthropods have bodies that are internally and externally segmented. The number of segments depends on the individual species; millipedes, for example, have more segments than lobsters. 3. Jointed Appendeges-The name arthropod actually comes from the Greek “arthro,” meaning joint, and “pod,” meaning foot. All arthropods have jointed limbs attached to their hard exoskeletons that allow for flexibility and movement. The joints generally bend in only one direction but allow for sufficient predatory and defensive actions. 4. Bilateral Symmetry-An arthropod's body can be divided vertically into two mirror images. This is called bilateral symmetry. An arthropod shares this symmetry with many other animals such as fish, mice and even humans. Other animals such as the jellyfish and sea star exhibit radial symmetry, while coral and sea sponge are asymmetrical -- exhibiting no pattern at all. 5. Open Circulation System-An arthropod has an open circulatory system. This means instead of a closed circulatory system of interconnected veins and capillaries, an arthropod’s blood is pumped through open spaces called sinuses in order to reach tissues. An arthropod does, however, have a heart which pumps blood into the hemocoel, the cavity where the organs are located, where it surrounds the organs and tissues.
DNA is the bio molecule that contains all of the organisms genes. when cell divides through mitosis, the daughter cells contains exact copies of DNA from both of its parents.
Hard-shelled organisms absorbed calcium and carbonate iron and use them in making their hard shells which are calcium carbonate. When these organisms die, there shells are used in the formation of limestone rock. Limestone rocks are a huge store carbon. When acid rain reacts with limestone, these trapped carbon are released to the atmosphere thereby causing an Increase in atmospheric carbon.
Conclusively, the accumulation of limestone rock and subsequent reactions with acids such as acid rain has resulted in an increased atmospheric carbon throughout the years.
Arabia or the Arabian Peninsula is a peninsula in Southwest Asia, northeast of Africa between the Red Sea in the west and the Persian Gulf in the east. The southern part of the peninsula is bounded by the Gulf of Aden in the southwest and the Gulf of Oman, and the Arabian Sea (Indian Ocean) in the southeast.
