What are the two most common minerals located in earth's crust?
a. diamonds and gold
b. feldspar and quartz
c. iron and copper
d. salt and saline

Brian's school locker has a three-digit combination lock that can be set using the numbers 5 to 9 (including 5 and 9), without repeating a number. the probability that the locker code begins with a prime number is %. the probability that the last digit of the locker code is an odd number is %.

Which layer surrounds the center of the earth? a: crust b: core c: mantle

Which statement best describes how chemical equations demonstrate conservation of mass?