Which organ covers the entire body and protects it?

If you were a single-celled organism and you lived in a nutrient-rich place, staying alive would be pretty straightforward. For instance, if you were an amoeba living in a pond, you could absorb nutrients straight from your environment. The oxygen you would need for metabolism could diffuse in across your cell membrane, and carbon dioxide and other wastes could diffuse out. When the time came to reproduce, you could just divide yourself in two! However, odds are you are not an amoeba—given that you're using Khan Academy right now—and things aren’t quite so simple for big, many-celled organisms like human beings. Your complex body has over 30 trillion cells, and most of those cells aren’t in direct contact with the external environment. 1 ^1 1 start superscript, 1, end superscript A cell deep inside your body—in one of your bones, say, or in your liver—can’t get the nutrients or oxygen it needs directly from the environment. Most cells in large multicellular organisms don't directly exchange substances like nutrients and wastes with the external environment, instead, they are surrounded by an internal environment of extracellular fluid—literally, fluid outside of cells. The cells get oxygen and nutrients from this extracellular fluid and release waste products into it. Humans and other complex organisms have specialized systems that maintain the internal environment, keeping it steady and able to provide for the needs of the cells. Different systems of the body carry out di...

Fill in the blank: In a___ environment, both animal and plant cells ______ as the water movesthe cell through the process of, Animal cells would die. In plant cells this process is called plasmolysis, or the plant cells are ___ (shrink) - this is when the plasma membrane pulls away from the cell wall, as excess water goes out of the cell. The cell wall protects the plan cell from dying right away and they can go back to normal when the concentration of solutes is lowered on the___ of the cell. When this happens, the water will move from a ___ solution towards a ___solution through the process of ___ ___. Which of the following best characterizes an angular unconformity? A) Tilted strata lie below the unconformity; bedding in younger strata above is parallel to the unconformity. B) Horizontal lava flows lie below the unconformity and horizontal, sedimentary strata lie above. C) The discordant boundary between older strata and an intrusive body of granite. D) Tilted strata lie below the unconformity with loose, unconsolidated soil above. 1. Which of the following elements would have similar properties to Sulfur? a. Chlorine b. Argon c. Aluminum d. Oxygen 2. Which element is likely to react violently with water (Hint: think back to the demo you saw!)? a. Beryllium b. Carbon c. Caesium d. Sulfur 3. Which element is most likely to be a clear, colourless, odourless gas that is unreactive? a. Fluorine b. Krypton c. Nitrogen d. Hydrogen 4. Which statement is correct? a. Be is more...

The integumentary system is a complex organ that helps protect the body and regulates various essential processes. It comprises the skin, hair, nails, and glands that produce sweat and oil. These tissues work together to protect the body from infection and injury and regulate bodily processes. The skin is the first line of defense against the outside world and is responsible for keeping the internal organs safe and healthy. It contains sweat glands that help fight overheating and This article looks at the integumentary system in more detail and highlights its essential biological roles and conditions that may affect it. Share on Pinterest Eduardo Parra/Europa Press via Getty Images The • hair • nails • glands As the • Protection: The skin and hair provide a barrier against harmful substances, ultraviolet (UV) radiation from the sun, and temperature extremes. • Sensation: The skin contains nerve endings that detect touch, pressure, pain, heat, and cold. • Temperature regulation: The skin can sweat and widen blood vessels to regulate body temperature. • Waste excretion: The skin eliminates some wastes through sweat. • Vitamin D production: When exposed to UV light from the sun, the skin produces Skin The skin is the body’s largest and heaviest organ. It covers the entire surface of the body and has multiple layers, each with different functions. It comprises • The epidermis: This is the outermost layer of the skin. It is thin and constantly shedding dead skin cells. • The de...