An endothermic reaction is defined as a reaction that .
A. requires heat or light
B. releases heat or light
C. has more than one product
D. has more than one reactant

Which branches of natural science include the study of an organism that lived 10 million years ago

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?

What is the main difference between the atmospheres of jupiter and neptune? a. neptune does not have hydrogen and helium. b. jupiter does not have hydrogen and helium. c. jupiter has methane clouds. d. neptune has methane clouds.