The absolute age of a rock is approximate number of years ago that the rock formed. The absolute age of an igneous rock can best be determind by A. measuring the amounts of radioactive isotopes in the rock
B. comparing the sizes of the crystals found in the upper and lower parts of a rock
C. examining the rock's relative position in a rock outcrop
D. observing the environment in which the rock is found

Air pressure is measured in pascals. for a professional american football game, the ball should be inflated to about 90,000 pascals. scientists studied the effects of air temperature on the pressure inside american footballs by taking these steps: 1. prepare 100 footballs. 2. measure each football's air pressure. 3. divide footballs into 10 groups. 4. place the groups in different lockers cooled to different air temperatures. 5. after 12 hours, remove the footballs from lockers. 6. measure each football's pressure again. 7. compare the new pressures to the starting pressures. what two terms best describe the variable "air pressure inside the football" in this experiment? independent, qualitative independent, quantitative dependent, qualitative dependent, quantitative