Answer to Question 1
The Search for ExtraTerrestrial Intelligence is a systematic project listening to radio waves worldwide, by many teams and individuals, in the hope of detecting the first proof that an intelligent civilization beyond our solar system is broadcasting signals, either to contact us, or from random broadcasts, much as we are now sending our radio signals all over the Galaxy.
Answer to Question 2
With current technology, space flight to the closest stars would still take thousands of years. Radio waves travel at the speed of light, and we have been broadcasting our location with commercial radio stations since the late 1930s. Everyone interested in such contact within 70 light-years has been able to receive our signals by now.
Answer to Question 3
Earth would be a stronger source of FM and TV waves than even our Sun. The peak signals would happen when eastern North America was rising or setting for the observer, and the entire pattern would repeat as the Earth rotated.
A plant response to flooding.
A stallion exhibiting the characteristics of a Flehmen response
Allergic response by allergens.
The CHRIS manual entry for toluene. Useful information includes response information, chemical and ...
The immune response results from activation of the humoral and cell-mediated immune systems
From Signal Reception to Response