Which of th following is an example of how scientist might use a model?
a. a hammer is used to nail two boards together
b. a timer is used to measure the amount of time the cake is in the oven
c. marbles placed inside a hollow sphere are used to describe protons in a nucleus
d. a magnifying glass is used to look at a ladybug

Identify the electromagnets with poles that are reversed from the electromagnet shown above

What is the mass of oxygen gas is consumed in a reaction that produces 4.60mol so2

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.