(N/A) $(1)$ The respiratory substrate,such as glucose,undergoes glycolysis in the cytoplasm (protoplasm) to produce pyruvic acid. This pyruvic acid then enters the mitochondria,where the Krebs cycle and oxidative phosphorylation take place. In these organelles,the respiratory substrate is completely oxidized,and energy is released in the form of $ATP$.
$(2)$ Unlike animals,plants do not possess specialized respiratory organs for gas exchange. Instead,they utilize stomata,lenticels,and general surface areas. Each part of the plant manages its own gas exchange requirements independently. Furthermore,the internal transport of gases between different plant parts is minimal,and the overall metabolic demand for gas exchange is lower in plants compared to animals. Consequently,the rate of respiration in plants is relatively slow.