If you want to create a program that will subtract two numbers that the user has inputted, what kind of variables do you need to create?

Afish fossil is found in a rock. a foot bone and tooth are found in an older layer of the same rock. what can scientists learn from the rock? a) the area changed from land to water. b) the area changed from water to land. c) the area has always been land. d) the area was once an ocean.