The author uses a word that means "a brief venture into a new field" in the text. Choose the word in the paragraph that MOST CLOSELY matches this meaning. Over the past 50 years, American and Soviet scientists have utilized the animal world for testing. Despite losses, these animals have taught the scientists a tremendous amount more than could have been learned without them. Without animal testing in the early days of the human space program, the Soviet and American programs could have suffered great losses of human life. These animals performed a service to their respective countries that no human could or would have performed. They gave their lives and/or their service in the name of technological advancement, paving the way for humanity's many forays into space.