Answer:
Prokaryotic Cells are cells that lack Cell Nucleus so the answer is bacteria
For a given wave in a given medium, if the frequency doubles,
the wavelength becomes 50% shorter.
That is, it becomes half as long as it was originally.
Explanation:
It is given that,
Velocity in East, 
Velocity in North, 
(a) The resultant velocity is given by :

(b) The width of the river is, d = 80 m
Let t is the time taken by the boat to travel shore to shore. So,


t = 16 seconds
(c) Let x is the distance covered by the boat to reach the opposite shore. So,


x = 48 meters
Hence, this is the required solution.
B. Both of these types of lenses have the ability to produce real images.
I would think the answer is c.