How does a laxative work? There are several different types of laxative, and they all work in different ways. Some add bulk to the stool, some soften it by helping it hold more water, some lubricate it, some pull water into the bowel, and some stimulate the nerves and muscles in the intestine. There are […]
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Why do insects have such short lives? Many insects seem to have short lives because they have evolved to prioritize rapid reproduction over a long life. However, it only seems that way if we focus on certain kinds of insects, or if we only look at their adult stage. Not all insects have short lives.
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Why don’t we notice when we blink? We don’t notice when we blink because our brain suppresses its visual center and makes sure our eyes are pointing in the same direction. Everybody is different, and we all blink a different number of times depending on the time of day, the condition of our eyes, the
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How does muscle memory work? Muscle memory works because the brain makes more efficient connections between neurons. We call it muscle memory because it feels like our muscles are working on their own, but the memory is down to the brain and the nervous system. The more you repeat an action, such as learning to
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How do we make blood? Blood is made in our red bone marrow in a process called hematopoiesis. People have different quantities of blood depending on their size, but it is usually about 8% of a person’s body weight. 55% of the blood is made up of plasma, and the other 45% is a combination
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Why do living things stop growing? Not all living things stop growing, but those that do stop for a number of different reasons. Mammals, birds, fish, reptiles, insects, and plants all follow different growth programs, and those programs reflect different body plans and different trade-offs. Not all living organisms stop growing. Plants and fungi often
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Why does an octopus have three hearts? An octopus has three hearts because getting oxygen from gills is hard work, and its copper-based blood does not carry oxygen as efficiently as human blood. Using three pumps keeps oxygen moving through the gills and around the body. The job of a heart is to keep blood
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Do all animals have imprinting? No, not all animals have imprinting, but a lot do. Imprinting is where a newborn animal learns to follow its protector as soon as it is born. When the animal is born, it imprints the closest animal, usually its mother, into its brain and then follows that animal exclusively. The
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What causes cataracts? Cataracts are caused when proteins in the lens break down and clump together, making the lens cloudy. Cataracts form in the lens of the eye. As the lens becomes cloudy, it can look whitish, and vision can become hazy, blurred, or glary. If left untreated, the cloudiness can increase until the lens
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How do ants farm aphids? Ants farm aphids by herding them together, feeding them, and keeping them out of the sight of predators. Aphids are small insects that suck the sap out of plants. They are usually between one and three millimeters long, and they have specialized mouth parts for cutting into plants and drinking
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