When comparing optical and radio telescopes, we know that both of these telescopes detect a certain band of the electromagnetic spectrum.
When contrasting optical and radio telescopes, we know that optical telescopes have higher equipment (polished mirrors, accuracy), and that they depend on weather. Radio telescopes have lower equipment (less precise reflectors), and depend on diff. things such as thermal radiation and man-made emissions.
Donkeys and horses can have a mule together, but the mule is unable to have offspring of its own. That is why horses and donkeys are considered to be different species - their offspring is infertile
