The have similar problems because since the cell has grown too large, it takes away nutrients that other cells need to survive. This is similar to too many users on a wireless network because with too many users, their is not enough network to supply each device on the wireless network.
The allele that is masked is recessive. The one which masks it is dominant.
100 centimeters make up one meter
The sisters are different heights because one or both of the parents has a short allele that wasnt dominated by the tall allele, or vice-versa.