<span>When there is no oxygen, or the organism cannot use oxygen for respiration.
</span>
Explanation:
In a food chain, only 10% of energy is transferred from one trophic level to another trophic level. If the energy produced at the producer level is 1000 J, then the energy available at the primary consumer level will be 100 J and energy available at the secondary consumer level will be 10 J.
<span>observations on the outcomes of breeding experiments. </span>
