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Ck 12: Life Science: Diabetes
[Free Registration/Login may be required to access all resource tools.] Diabetes is a non-infectious disease in which the body is unable to control the amount of sugar in the blood. People with diabetes have high blood sugar, either...
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Ck 12: Life Science: Muscles and Exercise
[Free Registration/Login may be required to access all resource tools.] Regular physical exercise is important in preventing lifestyle diseases such as cardiovascular disease, some types of cancer, type 2 diabetes, and obesity. Regular...
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Ck 12: Life Science: Tropisms
[Free Registration/Login may be required to access all resource tools.] Plants may not be able to move, but they are able to change how they grow in response to their environment. Growth toward or away from a stimulus is known as a...
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Ck 12: Life Science: Adulthood and Aging
[Free Registration/Login may be required to access all resource tools.] When is a person considered an adult? That depends. Most teens become physically mature by the age of 16 or so. But they are not adults in a legal sense until they...
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Ck 12: Life Science: Arachnids
[Free Registration/Login may be required to access all resource tools.] Arachnids are a class of joint-legged invertebrates in the subphylum Chelicerata. They live mainly on land but are also found in freshwater and in all marine...
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Ck 12: Life Science: Bony Fish
[Free Registration/Login may be required to access all resource tools.] There are almost 27,000 species of bony fish, which are divided into two classes: ray-finned fish and lobe-finned fish. Most bony fish are ray-finned. These thin...
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Ck 12: Life Science: Chordates
[Free Registration/Login may be required to access all resource tools.] Did you know that fish, amphibians, reptiles, birds, and mammals are all related? They are all chordates. Chordates are a group of animals that includes vertebrates,...
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Ck 12: Life Science: Diffusion
[Free Registration/Login may be required to access all resource tools.] The process of molecules moving from an area where there are lots of molecules to an area where there are fewer molecules is known as diffusion. The diffusion of...
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Ck 12: Life Science: Flatworms
[Free Registration/Login may be required to access all resource tools.] The word "worm" is not very scientific. But it is a word that informally describes animals (usually invertebrates) that have long bodies with no arms or legs. Worms...
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Ck 12: Life Science: Processes of Breathing
[Free Registration/Login may be required to access all resource tools.] Breathing is only part of the process of bringing oxygen to where it is needed in the body. After oxygen enters the lungs, what happens? Learn more about processes...
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Ck 12: Life Science: Alligators and Crocodiles
[Free Registration/Login may be required to access all resource tools.] Crocodilia, containing both alligators and crocodiles, is an order of large reptiles. Reptiles belonging to Crocodilia are the closest living relatives of birds....
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Ck 12: Life Science: Angiosperms
[Free Registration/Login may be required to access all resource tools.] Angiosperms, in the phylum Anthophyta, are the most successful phylum of plants. Angiosperms evolved the structure of the flower, so they are also called the...
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Ck 12: Life Science: Arthropods
[Free Registration/Login may be required to access all resource tools.] How often do you think you see an arthropod? With over a million described species in the phylum containing arthropods, chances are you encounter one of these...
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Ck 12: Life Science: Blood Types
[Free Registration/Login may be required to access all resource tools.] Do you know what your blood type is? Maybe you have heard people say that they have Type A or Type O blood. Blood type is a way to describe the type of antigens, or...
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Ck 12: Life Science: Cnidarians
[Free Registration/Login may be required to access all resource tools.] Cnidarians, in the phylum Cnidaria, include organisms such as the jellyfish and sea anemones. These animals are found in shallow ocean water. Learn more about...
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Ck 12: Life Science: Organelles
[Free Registration/Login may be required to access all resource tools.] All organelles are found in eukaryotic cells, while most are not found in prokaryotic cells. Learn more about organelles in this learning module produced by CK-12.
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Ck 12: Life Science: Origins of Life
[Free Registration/Login may be required to access all resource tools.] There is good evidence that life has probably existed on Earth for most of Earth's history. Fossils of blue-green algae found in Australia are the oldest fossils of...
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Ck 12: Life Science: Roundworms
[Free Registration/Login may be required to access all resource tools.] The word "worm" is not very scientific. This informal term describes animals that have long bodies with no arms or legs. Worms with round, non-segmented bodies are...
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Ck 12: Life Science: Crustaceans
[Free Registration/Login may be required to access all resource tools.] Crustaceans are a large group of arthropods, consisting of almost 52,000 species. The majority of crustaceans are aquatic. A few groups have adapted to living on...
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Ck 12: Life Science: Echinoderms
[Free Registration/Login may be required to access all resource tools.] You're probably familiar with starfish and sand dollars. They are both echinoderms. Sea urchins and sea cucumbers are also echinoderms. What's similar between these...
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Ck 12: Life Science: Gymnosperms
[Free Registration/Login may be required to access all resource tools.] Gymnosperms have seeds, but they do not produce fruit. Instead, the seeds of gymnosperms are usually found in cones. Learn more about gymnosperms in this learning...
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Ck 12: Life Science: Homeostasis
[Free Registration/Login may be required to access all resource tools.] When you walk outside on a cool day, does your body temperature drop? No, your body temperature stays stable at around 98.6 degrees Fahrenheit. Even when the...
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Ck 12: Life Science: Insect Food
[Free Registration/Login may be required to access all resource tools.] Insects have different types of appendages adapted for capturing and feeding on prey. They also have special senses that help them detect prey. Furthermore, insects...
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Ck 12: Life Science: Keeping Bones and Joints Healthy
[Free Registration/Login may be required to access all resource tools.] You can help keep your bones and skeletal system healthy by eating well and getting enough exercise. Weight-bearing exercises help keep bones strong. Learn more...