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Evolution by natural selection needs three conditions to be satisfied: variation, heredity, and competition (also called differential fitness).

1. There must be variation in a popula...

Homeostasis can simply be described as the maintenance of a constant internal environment. Human bodies must get rid of accumulating toxic substances which can harm the body. Things like sugar concentrati...

There are numerous ionic fluxes during an action potential, which involves depolarisation, repolarisation and hyperpolarsation. During depolarisation, voltage-gated sodium ion channels open. In turn, sodi...

The atria have a shorter contraction time as the ventricles as they only need to pump blood into the ventricles. The contraction time of the ventricles is longer as they need to pump blood through the aor...

Mitosis is the process by which a cell divides to give rise to two identical diploid daughter cells and is how all somatic cells are produced. Meiosis is the process by which a cell gives rise to four gen...