The writing materials,the envelopes and the stamps are all made of paper and this led to a great waste as the papers have to be disposed after use. This is not the case with electronic mails. Electronic mails do not need paper at all and it has drastically reduce the amount of papers that is used in writing letters.
I hope this helps :)
Answer:
Active Transport
Explanation:
Active transport is the process of transport of substances from region of their lower to that of higher concentration. Since the transport occurs against the concentration gradient, it is energy requiring process and needs input of energy to occur.
In given example, liver cells transports vitamins against the concentration gradient in energy dependent manner. Therefore, it is an example of "active transport".
F=ma
m=40 kg
a= unknown
f= 400 N
rearrange equation to f/m=a
so (400)/(40) = 10 m/s/s