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Ck 12: Life Science: Cardiovascular Diseases
[Free Registration/Login may be required to access all resource tools.] A cardiovascular disease (CVD) is any disease that affects the cardiovascular system. But the term is usually used to describe diseases that are linked to...
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Ck 12: Life Science: Characteristics of Life
[Free Registration/Login may be required to access all resource tools.] How do you define a living thing? What do mushrooms, daisies, cats, and bacteria have in common? All of these are living things, or organisms. It might seem hard to...
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Ck 12: Life Science: Diseases of the Nervous System
[Free Registration/Login may be required to access all resource tools.] The nervous system controls sensing, feeling, and thinking. It also controls movement and just about every other body function. That's why problems with the nervous...
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Ck 12: Life Science: Health of the Digestive System
[Free Registration/Login may be required to access all resource tools.] Most people have problems with their digestive system once in a while. These could be symptoms of foodborne illness, food allergies, or a food intolerance. Learn...
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Ck 12: Life Science: Injuries of the Nervous System
[Free Registration/Login may be required to access all resource tools.] Injuries to the central nervous system may damage tissues of the brain or spinal cord. If an injury is mild, a person may have a full recovery. If an injury is...
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Ck 12: Life Science: Levels of Ecological Organization
[Free Registration/Login may be required to access all resource tools.] Ecosystems are organized into several different levels, and they can be studied at any one of the various levels of organization. Learn more about levels of...
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Ck 12: Life Science: Bacteria Characteristics
[Free Registration/Login may be required to access all resource tools.] Bacteria are the most successful organisms on the planet. They lived on this planet for two billion years before the first eukaryotes and, during that time, evolved...
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Ck 12: Life Science: Enzymes in the Digestive System
[Free Registration/Login may be required to access all resource tools.] Chemical digestion could not take place without the help of digestive enzymes. An enzyme is a protein that speeds up chemical reactions in the body. Digestive...
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Ck 12: Life Science: Centipedes and Millipedes
[Free Registration/Login may be required to access all resource tools.] Centipedes and millipedes belong to the subphylum Myriapoda, which contains 13,000 species. They all live on land. They are divided among four classes: (1) Chilopoda...
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Ck 12: Life Science: Consumers and Decomposers
[Free Registration/Login may be required to access all resource tools.] Producers make their own food through photosynthesis. But many organisms are not producers and cannot make their own food, but must get their energy from other...
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Ck 12: Life Science: Excretory System Problems
[Free Registration/Login may be required to access all resource tools.] The urinary system controls the amount of water in the body and removes wastes. Any problem with the urinary system can also affect many other body systems. Learn...
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Ck 12: Life Science: Mammal Classification
[Free Registration/Login may be required to access all resource tools.] Traditionally, mammals were divided into groups based on their characteristics. Scientists took into consideration their anatomy, their habitats, and their feeding...
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Ck 12: Life Science: Respiratory System Health
[Free Registration/Login may be required to access all resource tools.] Many of the diseases related to smoking are called lifestyle diseases: diseases that are caused by choices that people make in their daily lives. For example, the...
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Ck 12: Life Science: Effects of Water Pollution
[Free Registration/Login may be required to access all resource tools.] Water pollutants can have an effect on both the ecology of ecosystems and on humans. As a result of water pollution, humans may not be able to use a waterway for...
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Ck 12: Life Science: Reproductive System Health
[Free Registration/Login may be required to access all resource tools.] Along with shin guards, a protective cup is useful in preventing injuries. Wearing a protective cup also prevents a potentially serious injury to the testes. Learn...
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Ck 12: Life Science: Sources of Water Pollution
[Free Registration/Login may be required to access all resource tools.] Water pollution is a serious issue facing hundreds of millions of people world-wide, having harmful effects on the lives of those people. Learn more about sources of...
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Ck 12: Life Science: Fields in the Life Sciences
[Free Registration/Login may be required to access all resource tools.] The life sciences are the study of living organisms. They deal with every aspect of living organisms, from the biology of cells to the biology of individual...
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Ck 12: Life Science: Safety in the Life Sciences
[Free Registration/Login may be required to access all resource tools.] There can be some very serious safety risks in scientific research. Safety practices must be followed when working with the hazardous materials and organisms. Learn...
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Ck 12: Life Science: Process of Cellular Respiration
[Free Registration/Login may be required to access all resource tools.] Why do you need air to live? Of course if you didn't breathe, you couldn't survive. You need the gas oxygen to perform cellular respiration to get energy from your...
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Ck 12: Life Science: Respiratory System Diseases
[Free Registration/Login may be required to access all resource tools.] Respiratory diseases are diseases of the lungs, bronchial tubes, trachea, nose, and throat. These diseases can range from a mild cold to a severe case of pneumonia....
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Ck 12: Life Science: Scientific Investigation
[Free Registration/Login may be required to access all resource tools.] The scientific method is a process used to investigate the unknown. It is the general process of a scientific investigation. This process uses evidence and testing....
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Ck 12: Life Science: Organization of Living Things
[Free Registration/Login may be required to access all resource tools.] When you see an organism that you have never seen before, you probably put it into a group without even thinking. If it is green and leafy, you probably call it a...
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Ck 12: Life Science: Timeline of Evolution
[Free Registration/Login may be required to access all resource tools.] For life to evolve from simple single-celled organisms to many millions of species of prokaryotic species to simple eukaryotic species to all the protists, fungi,...
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Ck 12: Life Science: Health Hazards of Air Pollution
[Free Registration/Login may be required to access all resource tools.] The World Health Organization (WHO) reports that 2.4 million people die each year from causes directly related to air pollution. Worldwide, there are more deaths...