Relative density, or specific gravity, is the ratio of the density of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water at its densest; for gases, the reference is air at room temperature.
Hey there,
Question : Which microbes can be Eukaryotic?
Answer : A, Bacteria
Hope this helps :D
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Answer : 2446 years.
Explanation :
Length of semi major axis is, 
According to Kepler's third law, square of time period of an orbit is directly proportional to the cube of the semi major axis.
i.e 
where G is gravitational constant
M is mass of sun, 
So, 




since, 
So, orbital period is approximately 2446 years.