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Explain the ways in which the structure of alveoli is related to its function

The alveolar epithelium is a site of rapid diffusion, consequently it is very thin, only one cell thick, providing a short diffusion pathway.Alveoli have constant blood flow and ventilation, maintaining a st...
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Answered by Joanne M. • Biology tutor
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Explain Cohesion-Tension Theory

Transpiration of water through stomata creates low potential at the top of the xylem. Water molecules stick together via hydrogen bonds in a process known as COHESION . This occurs because water molecules ar...
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Answered by Joanne M. • Biology tutor
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Describe and explain the photoelectric effect.

Consider a single photon (a particle of light) of a particular energy striking the surface of a metal. If the energy of this photon exceeds the work function of the metal, it will remove a single electron - ...
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Answered by Abbie R. • Physics tutor
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Explain how red-shift provides evidence for the Big Bang theory.

Red-shift describes the phenomenon whereby the wavelength of light from a source increases as it travels through spacetime, hence observed as being 'shifted' to the red end of the spectrum (as red light has ...
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Answered by Abbie R. • Physics tutor
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Explain what happens when an impulse arrvies at a junction between two neurones

At each junction there is a neurone that comes before it called the presynaptic neurone and one that comes after called the post synaptic neurone and the space between the two neurones is called the synapse....
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Answered by amy b. • Biology tutor
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