Invertebrates have a higher net production efficiency than mammals. Which statement most likely explains this observation? A. Invertebrates are more abundant than mammals in an ecosystem. B. Mammals maintain their body temperature; invertebrates don't. C. Most mammals are secondary consumers. Most invertebrates are primary consumers. D. Invertebrates have smaller bodies than mammals.

Net production efficiency (NPE) refers to how efficient an organism at one trophic level is in utilizing and transferring energy to the next trophic level. Consumer organisms obtain energy (from biomass) when they feed on other organisms. They then use this energy for their metabolic activities and transfer the rest when eaten or fed on.

The net production efficiency decreases with increasing trophic level because higher organisms use more energy than lower ones. In this case, invertebrates use energy they obtained lesser or more efficiently than mammals, hence, making them have a HIGHER net production efficiency than mammals. Therefore, invertebrates are mostly primary consumers and utilize energy lesser than mammals which are mostly SECONDARY CONSUMERS.