Earth’s Relief and Features

Coastal zones are areas where the emerged land surface meets the sea. These zones exhibit various landforms, including capes, gulfs, peninsulas, estuaries or fjords, and islands.

  • Cape: A part of the land that extends into the sea. A very small cape is called a point.
  • Gulf: An inlet of the sea along the coast. A small gulf is called a bay.
  • Peninsula: An area of land surrounded by water on all sides except for one, which is called an isthmus.
  • Estuary or Fjord: A deep, narrow valley flooded by the sea.
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Landforms: Mountains, Valleys, Plains, and Other Features

Landforms

Valleys

A valley is an elongated depression of land, more or less wide, crossed by a stream or a glacier.

  • Longitudinal Valley: A valley whose course is parallel to the general direction of a mountain range.
  • Transversal Valley: A valley that cuts at right angles to a mountain range.
  • U-Shaped Valley (Trough): A flat-bottomed glacial valley with steep slopes resulting from glacial erosion.
  • V-Shaped Valley: A river valley formed by the flow of a river.

Plateaus and Mountains

A plateau is a slightly

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Natural Hazards: Earthquakes and Volcanoes

The Genetic Code

The genetic code defines the relationship between nucleotides in a polynucleotide and amino acids.

This code is universal, meaning all living organisms, from bacteria to humans, share it. This universality provides further evidence of the unity of life and our shared evolutionary history.

Four distinct types of nucleotides, represented by their bases, exist in nucleic acids. Proteins, on the other hand, are composed of 20 different amino acids.

Seismic Risk

Areas with high tectonic

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Energy Types and Sources: Renewable and Non-Renewable

Energy

Energy is a physical quantity associated with the ability to produce changes in bodies. It is measurable and expressed in Joules. (1 cal = 4.19 J) (1 kWh = 3,600,000 J)

Types of Energy

Mechanical Energy

The sum of kinetic and potential energy.

Kinetic Energy

Energy possessed by a moving body.

Potential Energy

Energy possessed by a body due to its position (e.g., height).

Electrical Energy

Generated by the movement of electrically charged particles, producing electrical current.

Internal Energy

Energy

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Radioactive Decay, Phytoremediation, and Bioremediation of Metals

Radioactive Clocks

Radioactive elements are unstable and disintegrate at a precise rhythm. To measure the speed of this decay, we consider the half-life, the time it takes for a quantity of the material to reduce by half.

Isotopes:

  • Chlorine-36. Half-life: 300,000 years.
  • Hydrogen-3 (Tritium). Half-life: less than 1 second.
  • Technetium-99. Half-life: 6 hours.
  • Carbon-14. Half-life: 5,730 years.

Technetium-99 and Hydrogen-3 isotopes cannot be used to determine the age of fossils due to their short half-lives.

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Spain’s Water Resources, Natural Risks, and Environmental Challenges

1.3 Water Resources and Use

1.3.1 Water Consumption

  • Consumers of water: Irrigation (80%), economic sectors, household use. Municipal use has increased to 160 liters/inhabitant/day.
  • Non-consumptive uses: Fishing, aquaculture, navigation.

1.3.2 Water Balance

Water resources primarily come from rainfall and aquifers. Only 32% is available, and less than half of that is utilized.

Water Deficit Problems:

  • Uneven resource distribution: Surplus in northern basins (North pit, Douro River) and scarcity in Mediterranean
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