Respuesta :
Answer:
because some chemical reactions release gases which may be odourless or may have smell, in order to identify it it is necessary to have a good sense of smell.
Smell is vital for survival of most humans and animals as it enables them to track food and water, find a mate and even communicate. Although our sense of smell is not as acute as other animals we know that humans are able to detect up to 10,000 different odor molecules.