Yes It Okay to Be Gay

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  • Topic: Bivalvia, Mollusca, Clam
  • Pages : 2 (494 words )
  • Download(s) : 80
  • Published : February 25, 2013
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Why is it that most rappers always try to talk about their struggle of being a hustler or something like that. Personally I do not have any struggle other than my parents dilling me about everything and talking about school when I personally think it is pointless Two class names used to describe mollusks having two shells are bivalves and pelecypods. The two anatomical features that keep the shells from coming apart are the hinges and adductor muscles. You can determine the age of a clam or mussel by looking at its shell. Each line is a new layer of shell that the clam produces as it grows. The lines form bands which represent about a years growth. Mollusks shells are hard due to the presence of the compound calcium carbonate. A thin membrane called the mantle lines the inside of both shells and protects the internal organs. The mantle contains shell glands that secrete calcium carbonate, creating the shell. An incurrent siphon is where water that contains foods and oxygen enters through here. Waste products of digestion and respiration are eliminated through the excurrent siphon. Bivalves are adapted to breathe under water by using gill membranes. They function like lungs that take in oxygen and give off carbon dioxide. Water currents containing plankton and organic debris pass through the clams siphon which is propelled by the ciliary action of the gill surfaces. The mucus that coats the surface of the gills and mantle captured the food along the clam’s mouth, located opposite its siphon. A one-way digestive tract is where the food is digested. Byssal threads are made of a fibrous protein and attach the mussel firmly to rocks and other hard substances. Mussels need them to firmly attach to rocks and other hard substrates. The oyster lives attached to substrates as well. The shells are rough and uneven. The flat upper shell fits almost like a lid on top of the curved lower shell. This lower shell secretes a type of cement that adheres to rocks and other hard...
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