Which layer of the Earth's atmosphere is characterized by the presence of the ionosphere and where auroras occur?

What is the chemical formula for hydrochloric acid?

Which element is essential for organic compounds but is not found in inorganic compounds?

What is the name of the massive cloud of gas and dust from which a star and its planets form?

What is the name of the process where a gas changes directly to a solid without passing through the liquid phase?

What is the law of reflection for light?

Which of the following is a fundamental force in nature that acts between all particles with mass?

In a chemical equation, what do the coefficients represent?

What is the critical angle in optics?

Which space mission discovered the first evidence of liquid water on Mars, suggesting the possibility of past life?