Because science involves a lot of replication to confirm results. That means without the systems, it would take a long time to get the results right.
Answer:
Mocous cell
Explanation:
literally, stomach have chief cell (zymogenic), parietal cell and mocous cell
hope this helps
I do think that they close to not allow too much of either water or air from entering.
the hollow tube allows water to flow easily.
https://www.bbc.co.uk/bitesize/guides/z28g7p3/revision/1
All living cells arise from pre existing cells.
Check it’s answer on internet