Longer than a larger star
This is an example of Human Genome Project. It was a global logical research extend with the objective of deciding the arrangement of nucleotide base matches that make up human DNA, and of recognizing and mapping the greater part of the qualities of the human genome from both a physical and a practical point of view.
It depends on the life stage that the star is in. Currently, in the mid-life stage, the sun is still fusing hydrogen into helium, so the maximum here is helium; however, far in the future when the star is nearing its final days, it can fuse atoms into elements as heavy as iron and nickel.
Light is a form of EM radiation.
EM radiation has no mass (it's just energy packets called photons).
EM radiation can travel through a vacuum. (The speed of light in a vacuum is called c and is around 300,000 m/s).
Hope this helps!