The rule for controls is that
a. controls are only necessary if you're not doing an experiment
b. everything should remain the same between experimental groups
c. there should be only one independent variable and one dependent variable
d. the only change we make between experimental groups is to the independent variable

Which of the following typically characterizes a tropical rainforests

In which of the following relationships is one organism always benefited while the other organism is always harmed

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.