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Global Climate Change01:50

Global Climate Change

Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
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What is Natural Selection?01:32

What is Natural Selection?

Natural selection is an evolutionary process in which individuals with survival-promoting traits reproduce at higher rates. These favorable traits become more common within a population or species. Naturally selected traits initially arise via random genetic mutations. In order for selection to occur, there must be variation within a population, the trait controlling the variation must be heritable, and there must be an evolutionary advantage for variation in the trait.
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Nature and Nurture01:10

Nature and Nurture

Many human characteristics, like height, are shaped by both nature—in other words, by our genes—and by nurture, or our environment. For example, chronic stress during childhood inhibits the production of growth hormones and consequently reduces bone growth and height. Scientists estimate that 70-90% of variation in height is due to genetic differences among individuals, and 10-30% of variation in height is due to differences in the environments that individuals experience,...
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Compounds Essential to Human Function01:25

Compounds Essential to Human Function

The human body is composed of cells that are fundamentally made up of several different molecules. These molecules are essential to carry out all physiological processes in the body and are broadly classified into organic and inorganic based on their chemical structures.
Inorganic Compounds Essential to Human Functioning
Inorganic compounds essential to human functioning include water, salts, acids, and bases. These compounds are inorganic, i.e., they do not have a carbon-hydrogen bond. Water...
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Essential Minerals for Bone Health01:31

Essential Minerals for Bone Health

The minerals contained in all of the food we consume are essential for our organ systems. However, certain essential minerals, such as calcium, phosphorus, magnesium, manganese, and fluoride, largely affect bone health.
Calcium and Phosphorus
Calcium is a critical component of bones, especially in the form of calcium phosphate and calcium carbonate. Since the body cannot make calcium, it must be obtained from the diet. However, calcium cannot be absorbed from the small intestine without...
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Introduction to Global Positioning System01:30

Introduction to Global Positioning System

The Global Positioning System (GPS) revolutionized positioning on Earth, providing precise location data through satellite ranging. The GPS system was developed in 1978 by the U.S. Department of Defense  for military use, and it became available for civilian applications in 1983, transforming fields including navigation, fleet management, and time synchronization for telecommunications systems.GPS consists of satellites in medium Earth orbit, about 20,200 kilometers above the surface,...
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