Explanation:
1. Phases of Venus: Galileo was the first astronomer to use a telescope to observe the celestial objects. Through a telescope he observed that Venus shows the phases just like the Moon. This proved the Heliocentric theory correct against the then prevalent Geocentric theory.
2. Law of Falling bodies: The acceleration due to gravity is independent of weight of the objects that means two bodies of different mass will hit the ground at the same time if dropped from the same height.
3. The uneven surface of the Moon: He observed that the surface of the Moon is uneven and rough.
4. Discovery of the 4 Moons of Jupiter
 
        
             
        
        
        
Yes, C is correct. It self explains itself as we know light travels through a vacuum ( doesn't need a medium) and light is a type of electromagnetic wave.
        
             
        
        
        
Answer: I = 3.6 m3
(C)
Explanation:
moment of inertia for spherically shaped object around it's center is given as 
I = (2/5) mr² 
substituting the r = 3m²
I = (2/5)*(9) m3
I = 3.6 m3
 
        
             
        
        
        
Answer:Sound waves are longitudinal waves that is, are transmitted in the same direction of oscillation of the particles in the medium. Electromagnetic waves are transverse ie, the electric and magnetic fields, which are perpendicular to each other, oscillate perpendicularly to the direction of wave propagation.
Explanation: