Answer:
I believe this is a pacemaker. It controls the heart when it starts to fail.
Explanation:
Anaerobic respiration does not require oxygen.
Answer:
relationships ecosystem
Explanation:
I think this is right but I don't have much info from the question
Environmental contaminants make their way into lakes, rivers, and groundwater and many other places. Animals drink that water. Our crops absorb that water that seeps into the soil, those crops are consumed by animals and humans. Therefore those animals are contaminated with whatever contaminant they consumed. In return those animals are ingested by the predator that consumes it therefore passing through the food chain.