If the fish starts swimming in the direction you found in (a) at a speed of 2 m/s, what would be the initial rate of change of the salt concentration at the fish’ position with respect to time?.

tube or goog will be great resources to find the answer to the question that you're asking

none, its a machine

nah.   i'm just sleepy.

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge