Answer:
Periosteum.
Explanation:
Periosteum is an extremely thin region of non-calcified tissue on the exterior of bones. It covers the entire surface of every bone in the body, with the exception of the joint-forming ends of bones where cartilage forms the bone’s outer layer.
They are called reactants
Answer:
d. All of the Earth's systems interact with each other.
Layer 8 is older than layer 1
Answer:
Consumer
Explanation:
Producers are organisms that make their own food (plants), hosts are, well, hosts for parasites, and decomposers break down dead organisms (like mushrooms), so your answer is consumer.