What is meant when it is said that stars have a life cycle?

stars produce living things.
stars travel in circular orbits during their lives
stars are born, mature, and eventually die.
stars move about in their galaxies

Acar's position in relation to time is plotted on the graph. what is the car's average velocity? a) 5 m/s b) 10 m/s c) 30 m/s d) 50 m/s

Achemistry student needs of 40ml diethylamine for an experiment. by consulting the crc handbook of chemistry and physics, the student discovers that the density of diethylamine is 0.7 . calculate the mass of diethylamine the student should weigh out. round your answer to significant digits.

The pressure proportional to the area a- inversely b- directly c- increase d-decrease