When a volumetric flask is filled to contain an accurately known volume: a.
the top of the meniscus must be at the etched or printed mark on the neck of the flask.
b.
the solution must be heated to its boiling point to fill the flask with vapor.
c.
the flask must be filled completely so that there is no air remaining in the flask.
d.
the bottom of the meniscus must be at the etched or printed mark on the neck of the flask.

Um i think answer is a

Starsstars are giant balls of hot gases that can produce their own light. stars give out energy by converting hydrogen gas into helium in their cores. stars are gigantic in size and have immense gravitational attraction. the sun is a medium sized star that gives us energy and makes life on earth possible.planetsplanets are large (almost) spherical objects that revolve around the sun. planets move in fixed orbits around the sun. there are 8 planets in our solar system. planets may be made of rocks, metals, gases like hydrogen, nitrogen and methane. the earth is also a planet and is the only place in the universe that we know that supports life. planets that revolve around other stars are called exoplanets.satellitessatellites are objects that revolve around planets. they form the essential part of the celestial bodies. these may be of natural origin or sent by humans. the moon is a natural satellite of the earth and revolves around it because it is bound by the earth’s gravitational pull. man also has placed artificial or man-made satellites around the earth and other planets to study them and for communication purposes.i think this is correct not 100%