(N/A) $(i)$ Two errors are:
$(a)$ The fuse is incorrectly connected to the neutral wire $(N)$; it must be connected to the live wire $(L)$ to ensure safety by breaking the circuit during a fault.
$(b)$ Bulb $B_{2}$ is not connected to the neutral wire,meaning the circuit for $B_{2}$ is incomplete and it will not glow.
$(ii)$ The element of an electric heater is made of a material with a high melting point (like nichrome) to withstand high temperatures without melting. In contrast,a fuse wire is made of a material with a low melting point so that it melts and breaks the circuit when excessive current flows.
$(iii)$ Two advantages of parallel connection over series connection are:
$(a)$ Each appliance receives the same potential difference (voltage) as the power supply.
$(b)$ Each appliance has a separate switch,allowing it to be turned $ON$ or $OFF$ independently without affecting other appliances.