Compare and contrast aufbau principle and the pauli exclusion principle.

Which is an example of a reversible physical change?

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium

What is the source of continuous heat and energy that we receive from the sun