What is the term for a cluster of stars bound together by gravity, with a spherical or irregular shape?

Which of the following is a transition metal?

Which layer of the Earth is responsible for the convection currents that drive plate tectonics?

What is the chemical formula for nitric acid?

What is the purpose of the endoskeleton in vertebrates?

What is the primary gas in Earth's atmosphere?

Which gas is responsible for the formation of the ozone layer in the Earth's atmosphere?

Which organelle is responsible for cellular respiration and energy production in eukaryotic cells?

Which of the following is an example of a convergent plate boundary?

Which planet is known for its prominent ring system, consisting of numerous ringlets made of ice and rock particles?