An element's atomic number is 91. how many protons would an atom of this element have? protons 

The table below shows the acceleration of gravity on different bodies in the solar system. on which body would a 10 kg lamp has the most gravitational potential energy when lifted to a height of 2 m? a. earth b. mars c. neptune d. uranus

The ozone hole appears in antarctica during

In an experiment, how can i change human errors? be specific.