Snakes generally belong to which trophic level?

The average trophic efficiency of transfer of energy from one trophic level to the higher trophic level is called

The statement, "Tiger is in the apex of food chain", indicates

If $20 \ J$ of energy is trapped at the producer level,then how much energy will be available to the peacock as food in the following food chain (in $J$)?
Plant $\rightarrow$ Mice $\rightarrow$ Snake $\rightarrow$ Peacock

Identify the missing link in the following food chain:
Plants $\to$ Insect $\to$ Frog $\to$ $A$ $\to$ Hawk.

What is the rate of energy loss at different trophic levels in an energy pyramid (in $\%$)?