How is excretion in plants useful to human beings?
The excretory products of the plants are converted into harmless chemicals.
There is no organised excretory systems in plants like animals. Although, some excretory products are released in gaseous or liquid forms from different systems. But the majority of harmful excretory compounds in plants are converted into harmless compounds. The harmless excretory products such as asafoetida, tarpene of conifers, wax, rubber etc., are useful for human beings. Thank You