Val works as a paleoclimatologist in Alaska. While studying ice core samples, she identifies an increase in the isotopic ratio of oxygen 10,000 years ago. From this discovery, she knows that Earth's temperature at that time was
✓ Aside from
temperature, Val can also learn about
✓ from the ice cores. Val's data suggests that she's uncovered a glacial
climate for this time period. During a glacial climate, Val knows, there would have been
sea level, compared to what
she witnesses today.

Apopulation of black bears depends on salmon from a stream for food. if a drought causes the stream to run dry one year, how will this likely impact the black bear population?

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.

The term facultative anaerobe refers to an organism that