Whenever scientists carefully measure any quantity many times, they expect that
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OPTIONS:
- all of the measurements will be exactly the same
- only two of the measurements will be exactly the same
- all but one of the measurements will be exactly the same
- most of the measurements will be close but not exactly the same

most of the measurements will be close but not exactly the same

Which of the following is a cause of the ocean levels periodically rising and then falling?
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OPTIONS:
- the slight tilt of the Moon
- the force of gravity from the Moon
- the convection within Earth's mantle
- the revolution of Earth around the Sun

the force of gravity from the Moon

This in turn causes the average temperature on Earth to rise. Which of the following observations supports that theory?
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OPTIONS:
- The summer of 1998 was one of the hottest summer seasons on record.
- Carbon dioxide gas from cars and industry is a product of burning that produces heat.
- Carbon dioxide in the upper atmosphere absorbs and re-emits heat radiated from Earth's surface.
- Radiation on Earth's surface is increasing because of a hole in the ozone layers.
Carbon dioxide in the upper atmosphere absorbs and re-emits heat radiated from Earth's surface.