A) transports oxygen and carbon dioxide for the respiratory system
Answer:
Secondary consumers.
Explanation:
In a trophic pyramid, there are conventionally four levels. From the bottom they are: Producers, Primary Consumers: Secondary Consumers, and at the top we have tertiary consumers. Each level generally consumes animals in the level below it. Producers consist of plants.
The substance that would be added in order to reverse the reaction would be any substance that is found in the product side. Adding a substance that tends to be a product will shift the equilibrium of the system and will allow the reaction to produce the substances that is found in the reactant side.
