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An excitation signal (an action potential) is created by the sinoatrial (SA) node.The wave of excitation spreads across the atria,causing them to contract.Upon reaching the atrioventricular (AV) node, the...

The DNA exists as a double helix. It consist of two intertwined polynucleotide chains that run anti-parallel (in opposite directions) to each other, resembling a ladder twisted around itself. The DNA pol...

Conclusions should be a round-up of your overall argument without majorly repeating the points in your essays! You want to start them with your final statement e.g 'the economy was the biggest factor in t...

Rationalising surds is the process of removing a square root from the bottom of a fraction. The way we do it is by using a little trick involving the difference of two squares.The difference of two square...

One way in which pressure groups help improve democracy is by giving minorities a chance to air opinions important to them which may get lost by political parties who are tying to please the majority of t...