A dictionary is best for researching a word's origins. The last option is correct.
A dictionary is a book or electronic resource which function is to list the words of a language (typically in alphabetical order) and to provide their meaning, or gives the equivalent words in another language, often also adding information about pronunciation, origin, and usage. Online, there are a wide range of dictionaries to choose as well.
Mutation in plants could lead to the plant taking over other plants area and in the process kill the other plants and unbalance nature. it could also creat superviruses that we won't be able to cure
