Answer:
These are a part of lab procedures:
1. Write a hypothesis to answer a question.
2. Write a title at the top of a completed lab report.
3. Record the time to complete a chemical reaction.
These are NOT a part of lab procedures:
1. Create a question on the cause of a chemical reaction.
Stars having less mass collapses early than those with more mass. This can be explained by Einstein's equation E=mc².
According to this equation, mass of stars is converted into light due to thermonuclear reactions occuring in the core of star which acts as engine of the stars. This thermonuclear reactions keeps star alive. Thermonuclear reactions occurs slowly in massive stars hence massive stars live more than light stars.
Yes, with simple machines
Red shift of distant galaxies
Because dark line spectra result from passing white light through ionized gasses and plasmas, which is what the atmosphere of stars are made of. These frequencies are scattered by the star's atmosphere as it leaves the surface (photosphere) of the star, and don't make it to earth.
