Population Size, Good Luck!
Why do plant cells have chloroplasts and cell walls?
the answer of this question is The cell wall surrounds the plasma membrane of plant cells and provides tensile strength and protection against mechanical and osmotic stress. and
this answer is for the cell wall
<span>The hypothesis was that the cause of stomach-ulcers
is Helicobacter pylori and not spicy food. Marshall and Warren were able to
prove that the main cause of peptic ulcers was the bacterium Helicobacter
pylori instead of the spicy foods and stress, which physicians believed were
the main causes of peptic ulcers at the time.</span>