An atomic model shows 19 protons, 20 neutrons, and 19 electrons. What is the mass number of the atom?

Arollercoaster car at the top of a hill has potential energy kinetic energy chemical energy light energy

The big bang nucleosynthesis theory states that elements were produced in the first few minutes of the big bang while elements have their origins in the interiors of stars, forming much later in the history of the universe.

If oil spills continue, all of the following should be expected except (2 points) death of aquatic life. polluted groundwater. decreased soil productivity. increased global temperatures.