If two sounds are at slightly different frequencies, beats can be heard at a frequency equal to the difference in frequency of the two sources.

Keep your choice of a major there is probably no single correct choice. a ) to yourself. b) in perspective. c) based solely on the expectations of others. d) all of the answer choices are correct.

Which of the following must happen in order for productivity to increase? a. production levels remain unchanged while inputs increase. b. production levels rise while inputs decrease. c. production levels fall while inputs increase.

Which statements are true for invasive species? 1. they always stabilize an ecosystem. 2. they’re always successful in adjusting to a new habitat. 3. they often compete with the native species for resources. 4. they have the ability to displace the native species. 5. they’re always pests.