Why is dissection an important part of a biology curriculum? Which animals and/or plants should be included in biological studies?

Dissection is important because it is usually the process of disassembling and observing something to determine its internal structure and as an aid to discerning the functions and relationships of its components.lt is necessary to use it in order to do much deeper research.Without to cut it out,we can only see the organism's cover,and it's not enough.However,l think the animals or the plants which is in danger should be included in biogical studies because after we keep on studying,it may have some breakthrough which can help them.