Answer: C) a factor that may affect an experiment or investigation
Explanation:
This is the best answer. A and B can be eliminated. D describes a controlled variable which is more specific than a scientific variable, thus C is the best answer. It is the best description of just a scientific variable.
Short answer:
It has a "birth" (in the nebula) just like humans are born inside their mothers.
It gets older and changes(in color which is due to its Temperature and in Size) just like humans as they go from babies to adults to elders. They also both die (Stars exploded or become black holes) stars "die out" and humans literally die. Both can die(not literally for stars) from old age.
<span>Messages to the brain travel along the nerves, which are strings of long thin cells called neurons</span>
Limestone.
It is a sedimentary rock composed of calcite and aragonite. It is used as a building material mainly because it is easily available and easy to work with.
Limestone is used in the manufacture of steel as it is the primary raw material that helps to remove impurities from the iron ore and produces waste matter that has low melting point and viscosity
