Answer:
Hope it helps you :)
Explanation in the pic above.
Answer:

Explanation:
Given that,
The speed of an electromagnetic wave traveling in a transparent nonmagnetic substance is given by :

Where
k is the dielectric constant of the substance.
v is the speed of light in water


So, the speed of light in water is 
Answer:
Vibrating means to move quickly to and fro.
Explanation:
Answer:
A. cell walls
Explanation:
Plants have cell walls but animals dont.
Answer:
A
Explanation:
Resistors in series add. There is only one path the current can take. That's why Christmas Tree lights sometimes give a lot of trouble. If a bulb burns out, it could be any one of them and time is needed to find the burned out bulb.
That being the case R = R1 + R2
R1 = 50 ohms
R2 = 50 ohms
R = 50 + 50
R = 100 ohms
Answer A