Answer: The correct answer is Option b. Distance.
Explanation:
Scientists and astronomers use this unit to measure the distance in space. A light year is a unit of distance and not time because light travels very fast and it travels a lot of distance in one year.
Light year is basically defined as how far the beam of light travels in a year.
Therefore, this light year is a unit of distance. Hence, the correct option is option b.
Airports use ramps to connect the plane to the airport and towing trucks use ramps to get the vehicles on the truck
Answer:
Ethanol-filled thermometers are used in preference to mercury for meteorological measurements of minimum temperatures and can be used down to −70 °C (−94 °F). The physical limitation of the ability of a thermometer to measure low temperature is the freezing point of the liquid used.
Answer: 
It is given that:
Density of material =ρ
radius of inner spherical shell = 
radius of outer spherical shell=
we know that the volume of sphere is 
Volume of the given spherical shell = 
Then mass of the spherical shell can be calculate as:
Mass, m=density/ volume
