The pyramid of energy is always ..........

Which of the following is $NOT$ a limitation of an ecological pyramid?

The tip of an ecological pyramid is occupied by

Which of the following statements is not correct?

Given below are two statements.
Statement $I$ - Smaller the food chain, more is the available energy at each trophic level.
Statement $II$ - Pyramid of energy can also be sometimes inverted.
In the light of the above statements, select the correct option given below:

The pyramid of number is based on