Final answer:
The Milky Way is a spiral-shaped galaxy, one of millions in the observable universe, and contains about 400 billion stars. Therefore, D) All of the above are true is the correct answer.
Step-by-step explanation:
The correct answer to the student's question is D) All of the above are true. Our Milky Way galaxy is indeed a spiral-shaped galaxy, which means it has a flat, rotating disk containing stars, gas, and dust, along with a central concentration of stars known as the bulge. It is also one of millions of galaxies in the observable universe. Additionally, it contains approximately 400 billion stars, making it a large galaxy with a vast number of stellar components.
The Milky Way is often compared to other spiral galaxies, such as the Andromeda galaxy, which is our closest neighboring giant spiral galaxy. Observations and pictures of nearby galaxies that have similarities to the Milky Way have been crucial for astronomers in understanding the properties and structure of our own galaxy.