a figure of speech involving the comparison of one thing with another thing of a different kind, used to make a description more emphatic or vivid.
since a simile is where you compare 2 things i imagine the similie would be somwhere were he is talking about the maple tree. "before your could say jack robbison they have gone and grown alot bigger than you ever thought they could"
i had some trouble looking for it and thats all that makes sense for the similie i belive.
Explanation:
The activities in which human beings are engaged in different kinds of economic works to generate income are called economic activities.
or in simple words
Any work from which we can generate income are called economic activities
hope this helps you