Scientists use radio technology in order to track endangered species. These include radio collars, tags and chips. These devices can then be tracked wither via satellites through GPS technology or by locating the radio waves emitted by these devices using receivers.
These devices have proven very helpful in tracking organisms and monitoring their populations.
Explanation:
Cancer occurs in dividing cells only because genetic materials divide into two equal portions during division. This process may be interrupted by carcinogenes or mutagenes to make mutate cells and then render them as cancer cells. In the brain, the cells are differentiated and there is no chance to start division, then how can cancer be found in the brain.