Questions

Resistivity :

Resistivity is a measure of the resistance to the flow of electrons. 

Conductivity :

Conductivity is just the inverse of resistivity, σ = 1/ρ, where σ is conductivity and ρ is resistivity.

Example:

Think of a pipe and water, the bigger the pipe, the easier water can flow and thus the lower the resistance. 

Bicycle is a compound machine in the above given options. A compound machine is a machine that is formed by two or more simple machines.

Accumulator register, Temporary register, Instruction register, Stack Pointer, Program Counter are the various registers in 8085

The main excretory organs of insects and spiders are Malpighian tubules.

Monopotassium tartarate was used in baking powder.