Question

Why do plants not need a respiratory system?

Answer 1

Because they don't have lungs. They have Stomata.

Answer 2

During daytime in photosynthesis,leaves produce oxygen some of which is used in respiration and the rest is diffused out.Plants need carbon dioxide to get the energy from food with the help of stomata by the process of photosynthesis .They breathe with the help of stomata in leaves,lenticels in stem and general surface of roots.
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