_____ describes the life cycle of a star.
Nuclear fusion
Nebular clouds
Stellar evolution
The big bang
The correct answer is "Stellar evolution." To understand the life cycle of a star, it's important to explain how we can arrive at this answer.
To figure out the life cycle of a star, we need to have some knowledge about stars and how they form and change over time. The following steps can help you arrive at the answer:
1. Start by gathering information about stars and their formation. Learn about the process of stellar evolution, which describes how a star changes throughout its lifetime. Stars go through different stages and eventually exhaust their nuclear fuel, leading to their final fate.
2. One important aspect to consider is nuclear fusion. Nuclear fusion is the process in which lighter elements, such as hydrogen, combine to form heavier elements, such as helium, while releasing vast amounts of energy. This process is the main source of energy for stars and influences their evolution.
3. Next, eliminate the answer choices that are not related to star life cycles. The big bang refers to the event that is believed to have started the expansion of the universe. Nebular clouds are the initial stages of star formation, but they do not encompass the entire life cycle.
4. Finally, after considering all the information gathered, the correct answer would be "Stellar evolution." This term encompasses the growth, changes, and eventual death of a star, as it goes through various stages like protostar, main sequence, red giant, and eventually, depending on its mass, white dwarf, neutron star, or black hole.
Remember, understanding the concepts and processes behind a topic is crucial when searching for the correct answer.