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Phospholipids play a huge role in the human body. They are the main components of the cell membranes. They have a hydrophobic and a hydrophilic part.

A waxy cuticle is present. This is a waterproof, transparent layer that prevents evaporation of water due to heat from the sun. Because it is transparent, it allows sunlight to pass through to the palisad...

The body has many ways in which it deals with 'foreign invaders', like a rhinovirus (the virus responsible for the common cold). Once an infective micro-organism enters the body, lots of different cell t...

gas exchange occurs in the alveolus of the lungs. Alveoli provide a good surface for gas exchange to take place.They provide a large surface area to volume ratio which increases the amount of gas that can...

Eutrophication is the process whereby excess fertiliser is added to fields by farmers. This fertiliser contaisn nitrates which are very sioluble and so easily runs off into rivers and lakes. Plants use ni...