How long do cfc molecules remain active in the stratosphere?
a. 10 to 50 years
b. 30 to 60 years
c. 60 to 120 years
d. 150 to 500 years

An experiment is designed to test the relationship between the initial height of a basketball before it is dropped to the height of its rebound bounce. the height of the rebound bounce is measured using a scale positioned behind the ball. in the above experiment, which condition would not be controlled? a). the starting height of the ballb). the surface the ball bounces on c). the type of ball d). the method to measure the rebound height of the ball

How does the amount of energy required to hold each proton and neutron in the nucleus compare to the energy released when they are removed?

An object weigh 40n in air ,weigh 20n when submerged in water,and 30n when submerged in a liquid of unknown liquid density.what is the density of unknown of liquid?