A layer of smooth cartilage at their ends, which cushions the bones and prevents them from rubbing directly against one another. The whole joint is also enclosed in a synovial capsule, which is full of synovial fluid. The synovial fluid acts like the oil in an engine, lubricating the joint and preventing the cartilage from becoming worn down.
Answer:
B
Explanation:
A) plants release oxygen and absorb CO2
252 Ma<span> (million years)
Please give brainliest
</span>