in comparing two ecosystems A and B it is observed that A has only 1st and 2nd order consumer while B has 3rd, 4th , 5th order consumers . which is more stable? why?

Ecosystem A will be more stable because according to ten percent law only 10% of energy is transferred from one trophic level to next. In ecosystem B, the 4th and 5th order consumer will have very less or no energy at all to sustain themselves.