Cellular respiration is called an aerobic process because it requires .

Cellular respiration is the process through which cells convert sugars into energy. The energy comes from the fuel molecules such as Glucose(sugar) or Lipids(fats). In cellular respiration, Glucose molecule is dismantled in the presence of oxygen. The bonds between the glucose break forming a simpler molecule and energy is released in small amounts. Some of the energy is stored by cell in the form of ATP while rest is lost as heat. So, ATP is formed from glucose through endergonic and exergonic reactions. The aerobic breakdown of glucose molecule accompanying synthesis of ATP is called celluar respiration. Carbon dioxide and water are produced as by-products.

Aerobic Reaction: Aero = air, bic = life and Respiration.

Most of the organisms are aerobes. They breakdown sugar involving participation of molecule of oxygen and release the energy in the form of ATP and release carbon dioxide and water as by-product.

Anaerobic Reaction: An = Without, aero = Air, bic = Life and Respiration.

Some organisms obtain energy by braking down sugar in absence of oxygen. This type of respiration is called anaerobic respiration and organism are called anaerobes. Many micro-organism including yeast can repire anaerobically.

There are 2 types of anaerobes,

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

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