Represent pre-existing molecule that has already chemically reacted with other elements to form a new substance that is involved in the chemical equation.

Which lists the main components of darwin’s theory of evolution? a. random mutations drive evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms do not change. b. natural selection drives evolution; the evolution of a population happens slowly; organisms have common ancestors; organisms change over time. c. natural selection drives evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms change over time. d. random mutations drive evolution; the evolution of a population happens rapidly; organisms have common ancestors; organisms do not change.

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?

Explain why electric current cannot exist if a current doesn't have a voltage source.