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What is the difference between excretion and egestion? Name three major organs of excretion in humans, the substances they excrete and the function of this excretion.

Excretion is the removal of toxic materials, waste products of metabolism and excess substances from organisms. Egestion is the passing out of undigested food as faeces, through the anus. Three major organs ...
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Answered by Lucy W. • Biology tutor
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Why do plants grow towards sunlight?

Plants have adapted to grow towards sunlight - an essential requirement for growth and survival. But how do they do this? An important factor in the control of plant growth is the hormone 'auxin', found with...
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Answered by Rachael D. • Biology tutor
19878 Views

Which enzymes are involved in digestion?

Several enzymes are involved in digestion. Amylase is produced by the salivary glands and pacreas and starts working as soon as food is ingested, breaking down starch into maltose in the mouth and also the s...
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Answered by Halcyon H. • Biology tutor
5972 Views

What are hormones and how do they differ from nerve cells (neurons)

Hormones are chemical messengers. They are released from special gland cells and travel in the bloodstream to reach their target organs, where they will have their effect. Whereas nerve cells carry electrica...
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Answered by Norviewu D. • Biology tutor
6628 Views

What is the structure of proteins?

Most proteins have 3 or 4 levels of structure which include the primary, secondary and tertiary structure, with many also having a Quaternary structure. Firstly, the primary structure is the unique sequence ...
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Answered by Katie D. • Biology tutor
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