To test this hypothesis, geologists around the globe measured iridium concentrations at sites known to be 66 million years old. Because geologists knew that asteroid impacts cause minerals to fracture, they also measured the clay layers for shock-fractured minerals, like quartz.

Approximately percent of the energy created by cell metabolism is used by the body to carry on its normal functions, such as respiration, digestion, reproduction, muscular movement, circulation, and cellular regrowth.

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.

What surprised you about the position of the letter e when you looked at it under the microscope? practice what did the microscope do to the letter e? remember that the letter e was in readable position when place on the microscope stage.