Because ideas about evolution by natural selection have never been proven false, what term can be used to describe evolution by natural selection?

What noticeable trend from this graph might be used to make a conclusion?

Hector is back from his morning run and is feeling light-headed because his energy is depleted which food item will provide him with a quick source of carbohydrates

Based on the observation that only male crickets produce a song, you hypothesize that a male's song is a form of communication to potential mates. you set up a simple experiment to test this hypothesis. in the laboratory, you place a male snowy tree cricket in enclosure a, which is adjacent to enclosureb. in enclosure b, you place other insects, one at a time, and observe their responses to the male's song. the enclosures are designed so that the two insects being tested cannot see or smell each other, but sound is transmitted from enclosure a to enclosureb.