I don't know I guess its the plate tectonics
The answer is C. nebular are star nurseries. When the massive gas being collapsing in its own weight. Local areas of gas begin to coalesce under gravity. Due to enormous pressure, nuclear fusion begins and a protostar is formed. The protostar grows into the sun as more hydrogen fuses at the core. The planetesimal materials at the edges of the protostellar discs coalesce to form planets that orbit the star.
Answer:
Option (B)
Explanation:
In the field of astronomy, the magnitude scale of star is usually defined as a logarithmic scale that measures the brightness of the star, and this directly the relative distance from the earth. This magnitude value is dependent on the two main factors, namely the its brightness and the distance from a fixed point.
The given visual magnitude of a star is 7.3, and is comparatively very less brighter. This shows a relatively very large distance from the earth and due to this large distance and low luminousity, this star is not visible to our naked eye.
Thus, the correct answer is option (B).
If we will connect the resistors 2ohms, 3ohms, 5ohms in series and the 10ohms resistance parallel then we get equivalent resistance of 5 ohms.
The equivalent circuit is,
R equivalent for the series connection is,

The equivalent resistance is 5 ohms.
So your friend is saying true.