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A test cross is used to discover the genotype of an individual by crossing two parents to see the phenoypic ratio of the offspring produced. A homozygous recessive individual (one with two recessive or sm...

Mark schemes for biology essays in AQA aren't like the six mark questions at GCSE. You have to cover the subject broadly at first and show that you have an overall understanding of the tpoic in question b...

The initial environment would be a harsh/hostile environment which few species would be adapted to. The volcanic rock would have to be broken down to form humus, only a little or none would have been avai...

What is a nerve synapse?

A synapse refers to the junction between two neurons. When an impulse (action potential) reaches the end of a neuron (the pre-synaptic neuron), the synapse allows this sign...

Before an action potential can even start, it is important to remember that there are already uneven concentrations of ions over the membrane. Potassium ions are at a higher concentration inside the cell,...