What changes are observed in energy at successive trophic levels in a food chain?

In an aquatic food chain,at which trophic level can a whale be placed?

Given below are two statements:
Statement $I$: In an ecosystem,there is a unidirectional flow of energy from the sun through producers to consumers.
Statement $II$: Ecosystems are exempted from the $2^{nd}$ law of thermodynamics.
In the light of the above statements,choose the most appropriate answer from the options given below:

Maximum biomass and variable organisms are found in

What is the approximate amount of carbon fixed in the biosphere annually through photosynthesis?

$X-$ Atmospheric input of phosphorus through rainfall is much smaller than carbon input.
$Y-$ The exchange of phosphorus between organisms and the environment is negligible.