Radiation, as an energy transfer mechanism, is especially important because radiation energy can travel without an intervening medium. everything radiates. radiation provides us with visible light. all of the above

because radiation energy can travel without an intervening medium

Explanation:

The radiation is the emission or the transmission of the energy in the form of the waves and parties through the spaces and is either found in the Xrays, UV rays and the gamma rays and the beta rays. The sun s a major source of the cosmic radiation.

It is the doctrine that the us had the right and duty to expand throughout north america. it just means they believed they had the right to expand westward and they did! they stated with the 13 colonies and then they kept moving gaining different territories throughout the years