Which of the following changes occurs naturally in a system over time?

How are elements arranged in a periodic table

Which statement is true about this reaction? 14n+1h 15o it is a practical source of energy on earth. it occurs only outside the solar system. its product is heavier than each of its reactants. it shows the critical mass of an element.

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?