Answer:
Musical
relating to music
Radical
a group of atoms behaving as a unit in a number of compounds.
Technical
of, involving, or concerned with applied and industrial sciences
It is important because the sources tell you whether the article was credible. When you have an article that has bad source, you are running the risk of having, wrong, opinionated data. This can discredit you paper if you use it.
Answer:
Altitude is the height of something from sea level or ground level
Explanation: